The verify_host_key function in sshconnect.c in the client in OpenSSH 6.6 and earlier allows remote servers to trigger the skipping of SSHFP DNS RR checking by presenting an unacceptable HostCertificate.

The remote Redhat Enterprise Linux 5 host has one or more packages installed that are affected by multiple vulnerabilities that have been acknowledged by the vendor but will not be patched.

  - openssh: MaxAuthTries limit bypass via duplicates in KbdInteractiveDevices (CVE-2015-5600)

  - openssh: possible fallback from untrusted to trusted X11 forwarding (CVE-2016-1908)

  - The default configuration of OpenSSH through 6.1 enforces a fixed time limit between establishing a TCP     connection and completing a login, which makes it easier for remote attackers to cause a denial of service     (connection-slot exhaustion) by periodically making many new TCP connections. (CVE-2010-5107)

Note that Nessus has not tested for these issues but has instead relied on the package manager's report that the package is installed.

The 'verify_host_key' function in sshconnect.c in the client in OpenSSH 6.6 and earlier allows remote servers to trigger the skipping of SSHFP DNS RR checking by presenting an unacceptable HostCertificate.

The remote NewStart CGSL host, running version MAIN 4.05, has openssh-latest packages installed that are affected by multiple vulnerabilities:

  - scp in OpenSSH 4.2p1 allows attackers to execute     arbitrary commands via filenames that contain shell     metacharacters or spaces, which are expanded twice.
    (CVE-2006-0225)

  - sshd in OpenSSH before 4.4, when using the version 1 SSH     protocol, allows remote attackers to cause a denial of     service (CPU consumption) via an SSH packet that     contains duplicate blocks, which is not properly handled     by the CRC compensation attack detector. (CVE-2006-4924)

  - Signal handler race condition in OpenSSH before 4.4     allows remote attackers to cause a denial of service     (crash), and possibly execute arbitrary code if GSSAPI     authentication is enabled, via unspecified vectors that     lead to a double-free. (CVE-2006-5051)

  - Unspecified vulnerability in the sshd Privilege     Separation Monitor in OpenSSH before 4.5 causes weaker     verification that authentication has been successful,     which might allow attackers to bypass authentication.
    NOTE: as of 20061108, it is believed that this issue is     only exploitable by leveraging vulnerabilities in the     unprivileged process, which are not known to exist.
    (CVE-2006-5794)

  - Unspecified vulnerability in the     linux_audit_record_event function in OpenSSH 4.3p2, as     used on Fedora Core 6 and possibly other systems, allows     remote attackers to write arbitrary characters to an     audit log via a crafted username. NOTE: some of these     details are obtained from third party information.
    (CVE-2007-3102)

  - The (1) remote_glob function in sftp-glob.c and the (2)     process_put function in sftp.c in OpenSSH 5.8 and     earlier, as used in FreeBSD 7.3 and 8.1, NetBSD 5.0.2,     OpenBSD 4.7, and other products, allow remote     authenticated users to cause a denial of service (CPU     and memory consumption) via crafted glob expressions     that do not match any pathnames, as demonstrated by glob     expressions in SSH_FXP_STAT requests to an sftp daemon,     a different vulnerability than CVE-2010-2632.
    (CVE-2010-4755)

  - The default configuration of OpenSSH through 6.1     enforces a fixed time limit between establishing a TCP     connection and completing a login, which makes it easier     for remote attackers to cause a denial of service     (connection-slot exhaustion) by periodically making many     new TCP connections. (CVE-2010-5107)

  - It was found that OpenSSH did not properly handle     certain AcceptEnv parameter values with wildcard     characters. A remote attacker could use this flaw to     bypass intended environment variable restrictions.
    (CVE-2014-2532)

  - It was discovered that OpenSSH clients did not correctly     verify DNS SSHFP records. A malicious server could use     this flaw to force a connecting client to skip the DNS     SSHFP record check and require the user to perform     manual host verification of the DNS SSHFP record.
    (CVE-2014-2653)

  - It was found that when OpenSSH was used in a Kerberos     environment, remote authenticated users were allowed to     log in as a different user if they were listed in the     ~/.k5users file of that user, potentially bypassing     intended authentication restrictions. (CVE-2014-9278)

  - It was discovered that the OpenSSH sshd daemon did not     check the list of keyboard-interactive authentication     methods for duplicates. A remote attacker could use this     flaw to bypass the MaxAuthTries limit, making it easier     to perform password guessing attacks. (CVE-2015-5600)

  - It was discovered that the OpenSSH sshd daemon fetched     PAM environment settings before running the login     program. In configurations with UseLogin=yes and the     pam_env PAM module configured to read user environment     settings, a local user could use this flaw to execute     arbitrary code as root. (CVE-2015-8325)

  - An information leak flaw was found in the way the     OpenSSH client roaming feature was implemented. A     malicious server could potentially use this flaw to leak     portions of memory (possibly including private SSH keys)     of a successfully authenticated OpenSSH client.
    (CVE-2016-0777)

  - An access flaw was discovered in OpenSSH; the OpenSSH     client did not correctly handle failures to generate     authentication cookies for untrusted X11 forwarding. A     malicious or compromised remote X application could     possibly use this flaw to establish a trusted connection     to the local X server, even if only untrusted X11     forwarding was requested. (CVE-2016-1908)

  - A covert timing channel flaw was found in the way     OpenSSH handled authentication of non-existent users. A     remote unauthenticated attacker could possibly use this     flaw to determine valid user names by measuring the     timing of server responses. (CVE-2016-6210)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

According to its self-reported version number, the remote pfSense install is prior to 2.2.5. It is, therefore, affected by multiple vulnerabilities as stated in the referenced vendor advisories.

CVE-2014-2653 The verify_host_key function in sshconnect.c in the client in OpenSSH 6.6 and earlier allows remote servers to trigger the skipping of SSHFP DNS RR checking by presenting an unacceptable HostCertificate.

CVE-2014-2532 sshd in OpenSSH before 6.6 does not properly support wildcards on AcceptEnv lines in sshd_config, which allows remote attackers to bypass intended environment restrictions by using a substring located before a wildcard character.

The remote OracleVM system is missing necessary patches to address critical security updates :

  - CVE-2015-5600: MaxAuthTries limit bypass via duplicates     in KbdInteractiveDevices (#1245969)

  - CVE-2016-3115: missing sanitisation of input for X11     forwarding (#1317816)

  - SSH2_MSG_DISCONNECT for user initiated disconnect follow     RFC 4253 (#1222500)

  - Add missing dot in ssh manual page (#1197763)

  - Fix minor problems found by covscan/gcc (#1196063)

  - Add missing options in man ssh (#1197763)

  - Add KbdInteractiveAuthentication documentation to man     sshd_config (#1109251)

  - Correct freeing newkeys structure when privileged     monitor exits (#1208584)

  - Fix problems with failing persistent connections     (#1131585)

  - Fix memory leaks in auditing patch (#1208584)

  - Better approach to logging sftp commands in chroot

  - Make sshd -T write all config options and add missing     Cipher, MAC to man (#1109251)

  - Add missing ControlPersist option to man ssh (#1197763)

  - Add sftp option to force mode of created files     (#1191055)

  - Do not load RSA1 keys in FIPS mode (#1197072)

  - Add missing support for ECDSA in ssh-keyscan (#1196331)

  - Fix coverity/gcc issues (#1196063)

  - Backport wildcard functionality for PermitOpen in     sshd_config file (#1159055)

  - Ability to specify an arbitrary LDAP filter in ldap.conf     (#1119506)

  - Fix ControlPersist option with ProxyCommand (#1160487)

  - Backport fix of ssh-keygen with error : gethostname:
    File name too long (#1161454)

  - Backport show remote address instead of UNKNOWN after     timeout at password prompt (#1161449)

  - Fix printing of extensions in v01 certificates     (#1093869)

  - Fix confusing audit trail for unsuccessful logins     (#1127312)

  - Don't close fds for internal sftp sessions (#1085710)

  - Fix config parsing quotes (backport) (#1134938)

  - Enable logging in chroot into separate file (#1172224)

  - Fix auditing when using combination of ForcedCommand and     PTY (#1131585)

  - Fix ssh-copy-id on non-sh remote shells (#1135521)

  - ignore SIGXFSZ in postauth monitor child (#1133906)

  - don't try to generate DSA keys in the init script in     FIPS mode (#1118735)

  - ignore SIGPIPE in ssh-keyscan (#1108836)

  - ssh-add: fix fatal exit when removing card (#1042519)

  - fix race in backported ControlPersist patch (#953088)

  - skip requesting smartcard PIN when removing keys from     agent (#1042519)

  - add possibility to autocreate only RSA key into     initscript (#1111568)

  - fix several issues reported by coverity

  - x11 forwarding - be less restrictive when can't bind to     one of available addresses (#1027197)

  - better fork error detection in audit patch (#1028643)

  - fix openssh-5.3p1-x11.patch for non-linux platforms     (#1100913)

  - prevent a server from skipping SSHFP lookup (#1081338)     (CVE-2014-2653)

  - ignore environment variables with embedded '=' or '\0'     characters (CVE-2014-2532)

  - backport ControlPersist option (#953088)

  - log when a client requests an interactive session and     only sftp is allowed (#997377)

  - don't try to load RSA1 host key in FIPS mode (#1009959)

  - restore Linux oom_adj setting when handling SIGHUP to     maintain behaviour over restart (#1010429)

  - ssh-keygen -V - relative-specified certificate expiry     time should be relative to current time (#1022459)

  - adjust the key echange DH groups and ssh-keygen     according to SP800-131A (#993580)

  - log failed integrity test if /etc/system-fips exists     (#1020803)

  - backport ECDSA and ECDH support (#1028335)

  - use dracut-fips package to determine if a FIPS module is     installed (#1001565)

  - use dist tag in suffixes for hmac checksum files     (#1001565)

  - use hmac_suffix for ssh[,d] hmac checksums (#1001565)

  - fix NSS keys support (#1004763)

  - change default value of MaxStartups - CVE-2010-5107 -     #908707

  - add -fips subpackages that contains the FIPS module     files (#1001565)

  - don't use SSH_FP_MD5 for fingerprints in FIPS mode     (#998835)

  - do ssh_gssapi_krb5_storecreds twice - before and after     pam sesssion (#974096)

  - bump the minimum value of SSH_USE_STRONG_RNG to 14     according to SP800-131A (#993577)

  - fixed an issue with broken 'ssh -I pkcs11' (#908038)

  - abort non-subsystem sessions to forced internal     sftp-server (#993509)

  - reverted 'store krb5 credentials after a pam session is     created (#974096)'

  - Add support for certificate key types for users and     hosts (#906872)

  - Apply RFC3454 stringprep to banners when possible     (#955792)

  - fix chroot logging issue (#872169)

  - change the bad key permissions error message (#880575)

  - fix a race condition in ssh-agent (#896561)

  - backport support for PKCS11 from openssh-5.4p1 (#908038)

  - add a KexAlgorithms knob to the client and server     configuration (#951704)

  - fix parsing logic of ldap.conf file (#954094)

  - Add HMAC-SHA2 algorithm support (#969565)

  - store krb5 credentials after a pam session is created     (#974096)

Updated openssh packages fix security vulnerabilities :

sshd in OpenSSH before 6.6 does not properly support wildcards on AcceptEnv lines in sshd_config, which allows remote attackers to bypass intended environment restrictions by using a substring located before a wildcard character (CVE-2014-2532).

Matthew Vernon reported that if a SSH server offers a HostCertificate that the ssh client doesn't accept, then the client doesn't check the DNS for SSHFP records. As a consequence a malicious server can disable SSHFP-checking by presenting a certificate (CVE-2014-2653).

It was discovered that OpenSSH clients did not correctly verify DNS SSHFP records. A malicious server could use this flaw to force a connecting client to skip the DNS SSHFP record check and require the user to perform manual host verification of the DNS SSHFP record.
(CVE-2014-2653)

It was found that when OpenSSH was used in a Kerberos environment, remote authenticated users were allowed to log in as a different user if they were listed in the ~/.k5users file of that user, potentially bypassing intended authentication restrictions. (CVE-2014-9278)

The openssh packages have been upgraded to upstream version 6.6.1, which provides a number of bug fixes and enhancements over the previous version.

Bug fixes :

  - An existing /dev/log socket is needed when logging using     the syslog utility, which is not possible for all chroot     environments based on the user's home directories. As a     consequence, the sftp commands were not logged in the     chroot setup without /dev/log in the internal sftp     subsystem. With this update, openssh has been enhanced     to detect whether /dev/log exists. If /dev/log does not     exist, processes in the chroot environment use their     master processes for logging.

  - The buffer size for a host name was limited to 64 bytes.
    As a consequence, when a host name was 64 bytes long or     longer, the ssh-keygen utility failed. The buffer size     has been increased to fix this bug, and ssh-keygen no     longer fails in the described situation.

  - Non-ASCII characters have been replaced by their octal     representations in banner messages in order to prevent     terminal re-programming attacks. Consequently, banners     containing UTF-8 strings were not correctly displayed in     a client. With this update, banner messages are     processed according to RFC 3454, control characters have     been removed, and banners containing UTF-8 strings are     now displayed correctly.

  - Scientific Linux uses persistent Kerberos credential     caches, which are shared between sessions. Previously,     the GSSAPICleanupCredentials option was set to 'yes' by     default. Consequently, removing a Kerberos cache on     logout could remove unrelated credentials of other     sessions, which could make the system unusable. To fix     this bug, GSSAPICleanupCredentials is set by default to     'no'.

  - Access permissions for the /etc/ssh/moduli file were set     to 0600, which was unnecessarily strict. With this     update, the permissions for /etc/ssh/moduli have been     changed to 0644 to make the access to the file easier.

  - Due to the KRB5CCNAME variable being truncated, the     Kerberos ticket cache was not found after login using a     Kerberos-enabled SSH connection. The underlying source     code has been modified to fix this bug, and Kerberos     authentication works as expected in the described     situation.

Enhancements :

  - When the sshd daemon is configured to force the internal     SFTP session, a connection other then SFTP is used, the     appropriate message is logged to the /var/log/secure     file.

  - The sshd-keygen service was run using the     'ExecStartPre=-/usr/sbin/sshd- keygen' option in the     sshd.service unit file. With this update, the separate     sshd-keygen.service unit file has been added, and     sshd.service has been adjusted to require     sshd-keygen.service.

Updated openssh packages that fix two security issues, several bugs, and add various enhancements are now available for Red Hat Enterprise Linux 7.

Red Hat Product Security has rated this update as having Moderate security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section.

OpenSSH is OpenBSD's SSH (Secure Shell) protocol implementation. These packages include the core files necessary for both the OpenSSH client and server.

It was discovered that OpenSSH clients did not correctly verify DNS SSHFP records. A malicious server could use this flaw to force a connecting client to skip the DNS SSHFP record check and require the user to perform manual host verification of the DNS SSHFP record.
(CVE-2014-2653)

It was found that when OpenSSH was used in a Kerberos environment, remote authenticated users were allowed to log in as a different user if they were listed in the ~/.k5users file of that user, potentially bypassing intended authentication restrictions. (CVE-2014-9278)

The openssh packages have been upgraded to upstream version 6.6.1, which provides a number of bug fixes and enhancements over the previous version. (BZ#1059667)

Bug fixes :

* An existing /dev/log socket is needed when logging using the syslog utility, which is not possible for all chroot environments based on the user's home directories. As a consequence, the sftp commands were not logged in the chroot setup without /dev/log in the internal sftp subsystem. With this update, openssh has been enhanced to detect whether /dev/log exists. If /dev/log does not exist, processes in the chroot environment use their master processes for logging.
(BZ#1083482)

* The buffer size for a host name was limited to 64 bytes. As a consequence, when a host name was 64 bytes long or longer, the ssh-keygen utility failed. The buffer size has been increased to fix this bug, and ssh-keygen no longer fails in the described situation.
(BZ#1097665)

* Non-ASCII characters have been replaced by their octal representations in banner messages in order to prevent terminal re-programming attacks. Consequently, banners containing UTF-8 strings were not correctly displayed in a client. With this update, banner messages are processed according to RFC 3454, control characters have been removed, and banners containing UTF-8 strings are now displayed correctly. (BZ#1104662)

* Red Hat Enterprise Linux uses persistent Kerberos credential caches, which are shared between sessions. Previously, the GSSAPICleanupCredentials option was set to 'yes' by default.
Consequently, removing a Kerberos cache on logout could remove unrelated credentials of other sessions, which could make the system unusable. To fix this bug, GSSAPICleanupCredentials is set by default to 'no'. (BZ#1134447)

* Access permissions for the /etc/ssh/moduli file were set to 0600, which was unnecessarily strict. With this update, the permissions for /etc/ssh/moduli have been changed to 0644 to make the access to the file easier. (BZ#1134448)

* Due to the KRB5CCNAME variable being truncated, the Kerberos ticket cache was not found after login using a Kerberos-enabled SSH connection. The underlying source code has been modified to fix this bug, and Kerberos authentication works as expected in the described situation. (BZ#1161173)

Enhancements :

* When the sshd daemon is configured to force the internal SFTP session, a connection other then SFTP is used, the appropriate message is logged to the /var/log/secure file. (BZ#1130198)

* The sshd-keygen service was run using the 'ExecStartPre=-/usr/sbin/sshd-keygen' option in the sshd.service unit file. With this update, the separate sshd-keygen.service unit file has been added, and sshd.service has been adjusted to require sshd-keygen.service. (BZ#1134997)

Users of openssh are advised to upgrade to these updated packages, which correct these issues and add these enhancements.

The remote Oracle Linux 7 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2015-0425 advisory.

    - add new option GSSAPIEnablek5users and disable using ~/.k5users by default CVE-2014-9278       (#1169843)
    - prevent a server from skipping SSHFP lookup - CVE-2014-2653 (#1081338)

Tenable has extracted the preceding description block directly from the Oracle Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Updated openssh packages that fix two security issues, several bugs, and add various enhancements are now available for Red Hat Enterprise Linux 6.

Red Hat Product Security has rated this update as having Moderate security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section.

OpenSSH is OpenBSD's SSH (Secure Shell) protocol implementation. These packages include the core files necessary for both the OpenSSH client and server.

It was discovered that OpenSSH clients did not correctly verify DNS SSHFP records. A malicious server could use this flaw to force a connecting client to skip the DNS SSHFP record check and require the user to perform manual host verification of the DNS SSHFP record.
(CVE-2014-2653)

It was found that OpenSSH did not properly handle certain AcceptEnv parameter values with wildcard characters. A remote attacker could use this flaw to bypass intended environment variable restrictions.
(CVE-2014-2532)

This update also fixes the following bugs :

* Based on the SP800-131A information security standard, the generation of a digital signature using the Digital Signature Algorithm (DSA) with the key size of 1024 bits and RSA with the key size of less than 2048 bits is disallowed after the year 2013. After this update, ssh-keygen no longer generates keys with less than 2048 bits in FIPS mode. However, the sshd service accepts keys of size 1024 bits as well as larger keys for compatibility reasons. (BZ#993580)

* Previously, the openssh utility incorrectly set the oom_adj value to
-17 for all of its children processes. This behavior was incorrect because the children processes were supposed to have this value set to 0. This update applies a patch to fix this bug and oom_adj is now properly set to 0 for all children processes as expected. (BZ#1010429)

* Previously, if the sshd service failed to verify the checksum of an installed FIPS module using the fipscheck library, the information about this failure was only provided at the standard error output of sshd. As a consequence, the user could not notice this message and be uninformed when a system had not been properly configured for FIPS mode. To fix this bug, this behavior has been changed and sshd now sends such messages via the syslog service. (BZ#1020803)

* When keys provided by the pkcs11 library were removed from the ssh agent using the 'ssh-add -e' command, the user was prompted to enter a PIN. With this update, a patch has been applied to allow the user to remove the keys provided by pkcs11 without the PIN. (BZ#1042519)

In addition, this update adds the following enhancements :

* With this update, ControlPersist has been added to OpenSSH. The option in conjunction with the ControlMaster configuration directive specifies that the master connection remains open in the background after the initial client connection has been closed. (BZ#953088)

* When the sshd daemon is configured to force the internal SFTP session, and the user attempts to use a connection other than SFTP, the appropriate message is logged to the /var/log/secure file.
(BZ#997377)

* Support for Elliptic Curve Cryptography modes for key exchange (ECDH) and host user keys (ECDSA) as specified by RFC5656 has been added to the openssh packages. However, they are not enabled by default and the user has to enable them manually. For more information on how to configure ECDSA and ECDH with OpenSSH, see:
https://access.redhat.com/solutions/711953 (BZ#1028335)

All openssh users are advised to upgrade to these updated packages, which contain backported patches to correct these issues and add these enhancements.

According to its banner, the version of OpenSSH running on the remote host is 6.1 through 6.6.

It is, therefore, affected by a host verification bypass vulnerability related to SSHFP and certificates that could allow a malicious SSH server to cause the supplied client to inappropriately trust the server.

It was discovered that OpenSSH clients did not correctly verify DNS SSHFP records. A malicious server could use this flaw to force a connecting client to skip the DNS SSHFP record check and require the user to perform manual host verification of the DNS SSHFP record.
(CVE-2014-2653)

It was found that OpenSSH did not properly handle certain AcceptEnv parameter values with wildcard characters. A remote attacker could use this flaw to bypass intended environment variable restrictions.
(CVE-2014-2532)

This update also fixes the following bugs :

  - Based on the SP800-131A information security standard,     the generation of a digital signature using the Digital     Signature Algorithm (DSA) with the key size of 1024 bits     and RSA with the key size of less than 2048 bits is     disallowed after the year 2013. After this update,     ssh-keygen no longer generates keys with less than 2048     bits in FIPS mode. However, the sshd service accepts     keys of size 1024 bits as well as larger keys for     compatibility reasons.

  - Previously, the openssh utility incorrectly set the     oom_adj value to -17 for all of its children processes.
    This behavior was incorrect because the children     processes were supposed to have this value set to 0.
    This update applies a patch to fix this bug and oom_adj     is now properly set to 0 for all children processes as     expected.

  - Previously, if the sshd service failed to verify the     checksum of an installed FIPS module using the fipscheck     library, the information about this failure was only     provided at the standard error output of sshd. As a     consequence, the user could not notice this message and     be uninformed when a system had not been properly     configured for FIPS mode. To fix this bug, this behavior     has been changed and sshd now sends such messages via     the syslog service.

  - When keys provided by the pkcs11 library were removed     from the ssh agent using the 'ssh-add -e' command, the     user was prompted to enter a PIN. With this update, a     patch has been applied to allow the user to remove the     keys provided by pkcs11 without the PIN.

In addition, this update adds the following enhancements :

  - With this update, ControlPersist has been added to     OpenSSH. The option in conjunction with the     ControlMaster configuration directive specifies that the     master connection remains open in the background after     the initial client connection has been closed.

  - When the sshd daemon is configured to force the internal     SFTP session, and the user attempts to use a connection     other than SFTP, the appropriate message is logged to     the /var/log/secure file.

  - Support for Elliptic Curve Cryptography modes for key     exchange (ECDH) and host user keys (ECDSA) as specified     by RFC5656 has been added to the openssh packages.
    However, they are not enabled by default and the user     has to enable them manually.

New openssh packages are available for Slackware 13.0, 13.1, 13.37, 14.0, 14.1, and -current to fix a security issue.

The remote Oracle Linux 6 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2014-1552 advisory.

    - prevent a server from skipping SSHFP lookup (#1081338) CVE-2014-2653
    - ignore environment variables with embedded '=' or '\0' characters CVE-2014-2532

Tenable has extracted the preceding description block directly from the Oracle Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Redhat Enterprise Linux 6 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2014:1552 advisory.

    OpenSSH is OpenBSD's SSH (Secure Shell) protocol implementation.
    These packages include the core files necessary for both the OpenSSH client     and server.

    It was discovered that OpenSSH clients did not correctly verify DNS SSHFP     records. A malicious server could use this flaw to force a connecting     client to skip the DNS SSHFP record check and require the user to perform     manual host verification of the DNS SSHFP record. (CVE-2014-2653)

    It was found that OpenSSH did not properly handle certain AcceptEnv     parameter values with wildcard characters. A remote attacker could use this     flaw to bypass intended environment variable restrictions. (CVE-2014-2532)

    This update also fixes the following bugs:

    * Based on the SP800-131A information security standard, the generation of     a digital signature using the Digital Signature Algorithm (DSA) with the     key size of 1024 bits and RSA with the key size of less than 2048 bits is     disallowed after the year 2013. After this update, ssh-keygen no longer     generates keys with less than 2048 bits in FIPS mode. However, the sshd     service accepts keys of size 1024 bits as well as larger keys for     compatibility reasons. (BZ#993580)

    * Previously, the openssh utility incorrectly set the oom_adj value to -17     for all of its children processes. This behavior was incorrect because the     children processes were supposed to have this value set to 0. This update     applies a patch to fix this bug and oom_adj is now properly set to 0 for     all children processes as expected. (BZ#1010429)

    * Previously, if the sshd service failed to verify the checksum of an     installed FIPS module using the fipscheck library, the information about     this failure was only provided at the standard error output of sshd. As a     consequence, the user could not notice this message and be uninformed when     a system had not been properly configured for FIPS mode. To fix this bug,     this behavior has been changed and sshd now sends such messages via the     syslog service. (BZ#1020803)

    * When keys provided by the pkcs11 library were removed from the ssh agent     using the ssh-add -e command, the user was prompted to enter a PIN.
    With this update, a patch has been applied to allow the user to remove the     keys provided by pkcs11 without the PIN. (BZ#1042519)

    In addition, this update adds the following enhancements:

    * With this update, ControlPersist has been added to OpenSSH. The option in     conjunction with the ControlMaster configuration directive specifies that     the master connection remains open in the background after the initial     client connection has been closed. (BZ#953088)

    * When the sshd daemon is configured to force the internal SFTP session,     and the user attempts to use a connection other than SFTP, the appropriate     message is logged to the /var/log/secure file. (BZ#997377)

    * Support for Elliptic Curve Cryptography modes for key exchange (ECDH) and     host user keys (ECDSA) as specified by RFC5656 has been added to the     openssh packages. However, they are not enabled by default and the user has     to enable them manually. For more information on how to configure ECDSA and     ECDH with OpenSSH, see: https://access.redhat.com/solutions/711953     (BZ#1028335)

    All openssh users are advised to upgrade to these updated packages, which     contain backported patches to correct these issues and add these     enhancements.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

sshd in OpenSSH before 6.6 does not properly support wildcards on AcceptEnv lines in sshd_config, which allows remote attackers to bypass intended environment restrictions by using a substring located before a wildcard character.

The verify_host_key function in sshconnect.c in the client in OpenSSH 6.6 and earlier allows remote servers to trigger the skipping of SSHFP DNS RR checking by presenting an unacceptable HostCertificate.

The version of OpenSSH running on the remote host is affected by multiple security bypass vulnerabilities :

  - sshd in OpenSSH versions before 6.6 do not properly     support wildcards on AcceptEnv lines in sshd_config,     which allow a remote attacker to bypass intended     environment restrictions by using a substring located     before a wildcard character. (CVE-2014-2532)

  - The verify_host_key function in sshconnect.c in the     OpenSSH client for versions 6.6 and earlier allows     remote servers to trigger the skipping of SSHFP DNS     checking by presenting an unacceptable HostCertificate.
    (CVE-2014-2653)

This update for OpenSSH fixes the following issues :

  - Exit sshd normally when port is already in use.
    (bnc#832628)

  - Use hardware crypto engines where available.
    (bnc#826427)

  - Use correct options for login when it is used.
    (bnc#833605)

  - Move FIPS messages to higher debug level. (bnc#862875)

  - Fix forwarding with IPv6 addresses in DISPLAY.
    (bnc#847710)

  - Do not link OpenSSH binaries with LDAP libraries.
    (bnc#826906)

  - Parse AcceptEnv properly. (bnc#869101, CVE-2014-2532)

  - Check SSHFP DNS records even for server certificates.
    (bnc#870532, CVE-2014-2653)

- environment variables with embedded '=' or '0'     characters are now ignored

    - prevents a server from skipping SSHFP lookup and       forcing a new-hostkey dialog by offering only       certificate keys

    - /etc/ssh/moduli is readable by all now

    - ssh-copy-id is run in so called legacy mode when       SSH_COPY_ID_LEGACY variable is set

Note that Tenable Network Security has extracted the preceding description block directly from the Fedora security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

- environment variables with embedded '=' or '\0'     characters are now ignored

    - prevents a server from skipping SSHFP lookup and       forcing a new-hostkey dialog by offering only       certificate keys

    - ssh-agent is now suspend-aware as it gets also       CLOCK_BOOTTIME time

    - /etc/ssh/moduli is readable by all now

    - sshd-keygen.service depends on existence of       /etc/ssh/ssh_host_ecdsa_key instead of       /etc/ssh/ssh_host_dsa_key by default

    - ssh-copy-id is run in so called legacy mode when       SSH_COPY_ID_LEGACY variable is set

Note that Tenable Network Security has extracted the preceding description block directly from the Fedora security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

Updated openssh packages fixes security vulnerabilities :

sshd in OpenSSH before 6.6 does not properly support wildcards on AcceptEnv lines in sshd_config, which allows remote attackers to bypass intended environment restrictions by using a substring located before a wildcard character (CVE-2014-2532).

Matthew Vernon reported that if a SSH server offers a HostCertificate that the ssh client doesn't accept, then the client doesn't check the DNS for SSHFP records. As a consequence a malicious server can disable SSHFP-checking by presenting a certificate (CVE-2014-2653).

Matthew Vernon discovered that OpenSSH did not correctly check SSHFP DNS records if a server presented an unacceptable host certificate. A malicious server could use this issue to disable SSHFP checking.

Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

Two vulnerabilities were discovered in OpenSSH, an implementation of the SSH protocol suite. The Common Vulnerabilities and Exposures project identifies the following problems :

  - CVE-2014-2532     Jann Horn discovered that OpenSSH incorrectly handled     wildcards in AcceptEnv lines. A remote attacker could     use this issue to trick OpenSSH into accepting any     environment variable that contains the characters before     the wildcard character.

  - CVE-2014-2653     Matthew Vernon reported that if a SSH server offers a     HostCertificate that the ssh client doesn't accept, then     the client doesn't check the DNS for SSHFP records. As a     consequence a malicious server can disable     SSHFP-checking by presenting a certificate.

  Note that a host verification prompt is still displayed before   connecting.

ID	Name	Product	Family	Severity
198928	RHEL 5 : openssh (Unpatched Vulnerability)	Nessus	Red Hat Local Security Checks	critical
701161	OpenSSH < 6.7 Security Bypass	Nessus Network Monitor	SSH	medium
127415	NewStart CGSL MAIN 4.05 : openssh-latest Multiple Vulnerabilities (NS-SA-2019-0146)	Nessus	NewStart CGSL Local Security Checks	critical
106497	pfSense < 2.2.5 Multiple Vulnerabilities (SA-15_08)	Nessus	Firewalls	high
91617	F5 Networks BIG-IP : OpenSSH vulnerabilities (K15780)	Nessus	F5 Networks Local Security Checks	medium
90076	OracleVM 3.3 / 3.4 : openssh (OVMSA-2016-0038)	Nessus	OracleVM Local Security Checks	medium
82348	Mandriva Linux Security Advisory : openssh (MDVSA-2015:095)	Nessus	Mandriva Local Security Checks	medium
82258	Scientific Linux Security Update : openssh on SL7.x x86_64 (20150305)	Nessus	Scientific Linux Local Security Checks	medium
81894	CentOS 7 : openssh (CESA-2015:0425)	Nessus	CentOS Local Security Checks	medium
81725	Oracle Linux 7 : openssh (ELSA-2015-0425)	Nessus	Oracle Linux Local Security Checks	critical
81635	RHEL 7 : openssh (RHSA-2015:0425)	Nessus	Red Hat Local Security Checks	medium
79184	CentOS 6 : openssh (CESA-2014:1552)	Nessus	CentOS Local Security Checks	medium
78655	OpenSSH SSHFP Record Verification Weakness	Nessus	Misc.	medium
78641	Scientific Linux Security Update : openssh on SL6.x i386/x86_64 (20141014)	Nessus	Scientific Linux Local Security Checks	medium
78588	Slackware 13.0 / 13.1 / 13.37 / 14.0 / 14.1 / current : openssh (SSA:2014-293-01)	Nessus	Slackware Local Security Checks	medium
78526	Oracle Linux 6 : openssh (ELSA-2014-1552)	Nessus	Oracle Linux Local Security Checks	medium
78413	RHEL 6 : openssh (RHSA-2014:1552)	Nessus	Red Hat Local Security Checks	medium
78312	Amazon Linux AMI : openssh (ALAS-2014-369)	Nessus	Amazon Linux Local Security Checks	medium
76168	AIX OpenSSH Vulnerability : openssh_advisory4.asc	Nessus	AIX Local Security Checks	medium
76141	SuSE 11.3 Security Update : openssh (SAT Patch Number 9357)	Nessus	SuSE Local Security Checks	medium
76140	SuSE 11.3 Security Update : openssh (SAT Patch Number 9357)	Nessus	SuSE Local Security Checks	medium
74384	Fedora 19 : openssh-6.2p2-8.fc19 (2014-6569)	Nessus	Fedora Local Security Checks	medium
74133	Fedora 20 : openssh-6.4p1-4.fc20 (2014-6380)	Nessus	Fedora Local Security Checks	medium
73444	Mandriva Linux Security Advisory : openssh (MDVSA-2014:068)	Nessus	Mandriva Local Security Checks	medium
73401	Ubuntu 12.04 LTS / 12.10 / 13.10 : openssh vulnerability (USN-2164-1)	Nessus	Ubuntu Local Security Checks	medium
73350	Debian DSA-2894-1 : openssh - security update	Nessus	Debian Local Security Checks	medium

Detections

Analytics

CVE-2014-2653

high

Tenable Plugins

critical

medium

critical

high

medium

medium

medium

medium

medium

critical

medium

medium

medium

medium

medium

medium

medium

medium

medium

medium

medium

medium

medium

medium

medium

medium