sshd in OpenSSH before 7.4 allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via an out-of-sequence NEWKEYS message, as demonstrated by Honggfuzz, related to kex.c and packet.c.

The remote Redhat Enterprise Linux 6 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: loading of untrusted PKCS#11 modules in ssh-agent (CVE-2016-10009)

  - openssh: Bounds check can be evaded in the shared memory manager used by pre-authentication compression     support (CVE-2016-10012)

  - The auth_parse_options function in auth-options.c in sshd in OpenSSH before 5.7 provides debug messages     containing authorized_keys command options, which allows remote authenticated users to obtain potentially     sensitive information by reading these messages, as demonstrated by the shared user account required by     Gitolite. NOTE: this can cross privilege boundaries because a user account may intentionally have no shell     or filesystem access, and therefore may have no supported way to read an authorized_keys file in its own     home directory. (CVE-2012-0814)

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 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 version of Junos OS installed on the remote host is affected by multiple vulnerabilities as referenced in the JSA11169 advisory.

  - Untrusted search path vulnerability in ssh-agent.c in ssh-agent in OpenSSH before 7.4 allows remote     attackers to execute arbitrary local PKCS#11 modules by leveraging control over a forwarded agent-socket.
    (CVE-2016-10009)

  - sshd in OpenSSH before 7.4, when privilege separation is not used, creates forwarded Unix-domain sockets     as root, which might allow local users to gain privileges via unspecified vectors, related to     serverloop.c. (CVE-2016-10010)

  - authfile.c in sshd in OpenSSH before 7.4 does not properly consider the effects of realloc on buffer     contents, which might allow local users to obtain sensitive private-key information by leveraging access     to a privilege-separated child process. (CVE-2016-10011)

  - The shared memory manager (associated with pre-authentication compression) in sshd in OpenSSH before 7.4     does not ensure that a bounds check is enforced by all compilers, which might allows local users to gain     privileges by leveraging access to a sandboxed privilege-separation process, related to the m_zback and     m_zlib data structures. (CVE-2016-10012)

  - sshd in OpenSSH before 7.4 allows remote attackers to cause a denial of service (NULL pointer dereference     and daemon crash) via an out-of-sequence NEWKEYS message, as demonstrated by Honggfuzz, related to kex.c     and packet.c. (CVE-2016-10708)

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

sshd in OpenSSH before 7.4 allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via an out-of-sequence NEWKEYS message, as demonstrated by Honggfuzz, related to kex.c and packet.c. (CVE-2016-10708)

Impact

This vulnerability allows a remote attacker to disrupt service.

The remote Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-3809-1 advisory.

    Robert Swiecki discovered that OpenSSH incorrectly handled certain messages. An attacker could possibly     use this issue to cause a denial of service. This issue only affected Ubuntu 14.04 LTS and Ubuntu 16.04     LTS. (CVE-2016-10708)

    It was discovered that OpenSSH incorrectly handled certain requests. An attacker could possibly use this     issue to access sensitive information. (CVE-2018-15473)

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

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

This update for openssh fixes the following issues :

Security issues fixed :

CVE-2018-15919: Remotely observable behaviour in auth-gss2.c in OpenSSH could be used by remote attackers to detect existence of users on a target system when GSS2 is in use. OpenSSH developers do not want to treat such a username enumeration (or 'oracle') as a vulnerability.
(bsc#1106163)

CVE-2017-15906: The process_open function in sftp-server.c in OpenSSH did not properly prevent write operations in readonly mode, which allowed attackers to create zero-length files. (bsc#1065000, bsc#1106726)

CVE-2016-10708: sshd allowed remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via an out-of-sequence NEWKEYS message, as demonstrated by Honggfuzz, related to kex.c and packet.c. (bsc#1076957)

CVE-2018-15473: OpenSSH was prone to a user existance oracle vulnerability due to not delaying bailout for an invalid authenticating user until after the packet containing the request has been fully parsed, related to auth2-gss.c, auth2-hostbased.c, and auth2-pubkey.c. (bsc#1105010)

CVE-2016-10012: Removed pre-auth compression support from the server to prevent possible cryptographic attacks. (bsc#1016370)

Bugs fixed: Fixed failing 'AuthorizedKeysCommand' within a 'Match User' block in sshd_config (bsc#1105180)

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

This update for openssh fixes the following issues :

Security issue fixed :

CVE-2016-10708: Prevent DoS due to crashes caused by out-of-sequence NEWKEYS message (bsc#1076957).

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

According to the version of the openssh packages installed, the EulerOS Virtualization installation on the remote host is affected by the following vulnerability :

  - sshd in OpenSSH before 7.4 allows remote attackers to     cause a denial of service (NULL pointer dereference and     daemon crash) via an out-of-sequence NEWKEYS message,     as demonstrated by Honggfuzz, related to kex.c and     packet.c.(CVE-2016-10708)

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

This update for openssh provides the following fixes :

Security issues fixed :

CVE-2017-15906: Stricter checking of operations in read-only mode in sftp server (bsc#1065000).

CVE-2016-10012: Remove pre-auth compression support from the server to prevent possible cryptographic attacks (bsc#1016370).

CVE-2008-1483: Refine handling of sockets for X11 forwarding to remove reintroduced CVE-2008-1483 (bsc#1069509).

CVE-2016-10708: Prevent DoS due to crashes caused by out-of-sequence NEWKEYS message (bsc#1076957).

Bug fixes: bsc#1017099: Enable case-insensitive hostname matching.

bsc#1023275: Add a new switch for printing diagnostic messages in sftp client's batch mode.

bsc#1048367: systemd integration to work around various race conditions.

bsc#1053972: Remove duplicate KEX method.

bsc#1092582: Add missing piece of systemd integration.

Remove the limit on the amount of tasks sshd can run.

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

This update for openssh fixes the following issues: Security issue fixed :

  - CVE-2016-10708: Prevent DoS due to crashes caused by     out-of-sequence NEWKEYS message (bsc#1076957).

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

This update for openssh fixes the following issues: Security issues fixed :

  - CVE-2016-10012: Fix pre-auth compression checks that     could be optimized away (bsc#1016370).

  - CVE-2016-10708: Fix remote denial of service (NULL     pointer dereference and daemon crash) via an     out-of-sequence NEWKEYSmessage (bsc#1076957).

  - CVE-2017-15906: Fix r/o sftp-server zero byte file     creation (bsc#1065000).

  - CVE-2008-1483: Fix accidental re-introduction of     CVE-2008-1483 (bsc#1069509). Bug fixes :

  - bsc#1017099: Match conditions with uppercase hostnames     fail (bsc#1017099)

  - bsc#1053972: supportedKeyExchanges     diffie-hellman-group1-sha1 is duplicated (bsc#1053972)

  - bsc#1023275: Messages suppressed after upgrade from SLES     11 SP3 to SP4 (bsc#1023275)

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

This update for openssh fixes the following issues :

Security issue fixed :

  - CVE-2016-10708: Prevent DoS due to crashes caused by     out-of-sequence NEWKEYS message (bsc#1076957).

This update was imported from the SUSE:SLE-12-SP2:Update update project.

According to the version of the openssh packages installed, the EulerOS installation on the remote host is affected by the following vulnerability :

  - sshd in OpenSSH before 7.4 allows remote attackers to     cause a denial of service (NULL pointer dereference and     daemon crash) via an out-of-sequence NEWKEYS message,     as demonstrated by Honggfuzz, related to kex.c and     packet.c.(CVE-2016-10708)

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

OpenSSH was found to be vulnerable to out of order NEWKEYS messages which could crash the daemon, resulting in a denial of service attack.

For Debian 7 'Wheezy', these problems have been fixed in version 1:6.0p1-4+deb7u7.

We recommend that you upgrade your openssh packages.

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

An update for openssh is now available for Red Hat Enterprise Linux 7.

Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server.

The following packages have been upgraded to a later upstream version:
openssh (7.4p1). (BZ#1341754)

Security Fix(es) :

* 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)

* It was found that OpenSSH did not limit password lengths for password authentication. A remote unauthenticated attacker could use this flaw to temporarily trigger high CPU consumption in sshd by sending long passwords. (CVE-2016-6515)

* It was found that ssh-agent could load PKCS#11 modules from arbitrary paths. An attacker having control of the forwarded agent-socket on the server, and the ability to write to the filesystem of the client host, could use this flaw to execute arbitrary code with the privileges of the user running ssh-agent. (CVE-2016-10009)

* It was found that the host private key material could possibly leak to the privilege-separated child processes via re-allocated memory. An attacker able to compromise the privilege-separated process could therefore obtain the leaked key information. (CVE-2016-10011)

* It was found that the boundary checks in the code implementing support for pre-authentication compression could have been optimized out by certain compilers. An attacker able to compromise the privilege-separated process could possibly use this flaw for further attacks against the privileged monitor process. (CVE-2016-10012)

Additional Changes :

For detailed information on changes in this release, see the Red Hat Enterprise Linux 7.4 Release Notes linked from the References section.

From Red Hat Security Advisory 2017:2029 :

An update for openssh is now available for Red Hat Enterprise Linux 7.

Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server.

The following packages have been upgraded to a later upstream version:
openssh (7.4p1). (BZ#1341754)

Security Fix(es) :

* 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)

* It was found that OpenSSH did not limit password lengths for password authentication. A remote unauthenticated attacker could use this flaw to temporarily trigger high CPU consumption in sshd by sending long passwords. (CVE-2016-6515)

* It was found that ssh-agent could load PKCS#11 modules from arbitrary paths. An attacker having control of the forwarded agent-socket on the server, and the ability to write to the filesystem of the client host, could use this flaw to execute arbitrary code with the privileges of the user running ssh-agent. (CVE-2016-10009)

* It was found that the host private key material could possibly leak to the privilege-separated child processes via re-allocated memory. An attacker able to compromise the privilege-separated process could therefore obtain the leaked key information. (CVE-2016-10011)

* It was found that the boundary checks in the code implementing support for pre-authentication compression could have been optimized out by certain compilers. An attacker able to compromise the privilege-separated process could possibly use this flaw for further attacks against the privileged monitor process. (CVE-2016-10012)

Additional Changes :

For detailed information on changes in this release, see the Red Hat Enterprise Linux 7.4 Release Notes linked from the References section.

The installed version of OpenSSH is 7.x prior to 7.4 and is affected by the following vulnerabilities :

 - A flaw exists in 'sshd(8)' that is triggered during the creation of forwarded Unix-domain sockets. This may allow a local attacker to potentially gain elevated privileges.
 - A flaw exists in the 'realloc()' function in 'sshd(8)' that is triggered when reading keys. This may allow a local attacker to gain access to potentially sensitive key material that is leaked by the system.
 - A flaw exists in 'ssh-agent(1)' that is triggered when invoking the PKCS#11 module during agent forwarding. This may allow a local attacker to potentially execute arbitrary code with elevated privileges.
 - A flaw exists in 'sshd(8)' that is triggered as bounds are not properly checked in pre-authentication compression support, while the shared memory manager may be inappropriately accessed. This may potentially allow a local attacker to gain elevated privileges.
 - A flaw exists in 'sshd(8)' that is triggered during the handling of a saturation of 'KEXINIT' messages. This may allow a remote attacker to cause a denial of service.
 - A flaw exists in 'sshd(8)' that is triggered during as address ranges for 'AllowUser' and 'DenyUsers' directives are not properly validated at configuration load time. This may allow a local attacker to potentially gain unintended access to restricted areas.
 - A flaw exists that allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via an out-of-sequence NEWKEYS message, as demonstrated by Honggfuzz, related to kex.c and packet.c.

According to its banner, the version of OpenSSH running on the remote host is prior to 7.4. It is, therefore, affected by multiple vulnerabilities :

  - A flaw exists in ssh-agent due to loading PKCS#11     modules from paths that are outside a trusted whitelist.
    A local attacker can exploit this, by using a crafted     request to load hostile modules via agent forwarding, to     execute arbitrary code. To exploit this vulnerability,     the attacker would need to control the forwarded     agent-socket (on the host running the sshd server) and     the ability to write to the file system of the host     running ssh-agent. (CVE-2016-10009)

  - A flaw exists in sshd due to creating forwarded     Unix-domain sockets with 'root' privileges whenever     privilege separation is disabled. A local attacker can     exploit this to gain elevated privileges.
    (CVE-2016-10010)

  - An information disclosure vulnerability exists in sshd     within the realloc() function due leakage of key     material to privilege-separated child processes when     reading keys. A local attacker can possibly exploit this     to disclose sensitive key material. Note that no such     leak has been observed in practice for normal-sized     keys, nor does a leak to the child processes directly     expose key material to unprivileged users.
    (CVE-2016-10011)

  - A flaw exists in sshd within the shared memory manager     used by pre-authenticating compression support due to a     bounds check being elided by some optimizing compilers     and due to the memory manager being incorrectly     accessible when pre-authenticating compression is     disabled. A local attacker can exploit this to gain     elevated privileges. (CVE-2016-10012)

  - A denial of service vulnerability exists in sshd when     handling KEXINIT messages. An unauthenticated, remote     attacker can exploit this, by sending multiple KEXINIT     messages, to consume up to 128MB per connection.

  - A flaw exists in sshd due to improper validation of     address ranges by the AllowUser and DenyUsers     directives at configuration load time. A local attacker     can exploit this, via an invalid CIDR address range, to     gain access to restricted areas.

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

ID	Name	Product	Family	Severity
198952	RHEL 6 : openssh (Unpatched Vulnerability)	Nessus	Red Hat Local Security Checks	high
198928	RHEL 5 : openssh (Unpatched Vulnerability)	Nessus	Red Hat Local Security Checks	critical
148681	Juniper Junos OS Multiple Vulnerabilities (JSA11169)	Nessus	Junos Local Security Checks	high
132548	F5 Networks BIG-IP : OpenSSH vulnerability (K32485746)	Nessus	F5 Networks Local Security Checks	high
118795	Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS : OpenSSH vulnerabilities (USN-3809-1)	Nessus	Ubuntu Local Security Checks	medium
118498	SUSE SLES11 Security Update : openssh (SUSE-SU-2018:3540-1)	Nessus	SuSE Local Security Checks	high
118285	SUSE SLES12 Security Update : openssh (SUSE-SU-2018:2530-2)	Nessus	SuSE Local Security Checks	high
117563	EulerOS Virtualization 2.5.0 : openssh (EulerOS-SA-2018-1254)	Nessus	Huawei Local Security Checks	high
117452	SUSE SLES12 Security Update : openssh (SUSE-SU-2018:2685-1)	Nessus	SuSE Local Security Checks	high
112148	SUSE SLES12 Security Update : openssh (SUSE-SU-2018:2530-1)	Nessus	SuSE Local Security Checks	high
111639	SUSE SLES11 Security Update : openssh (SUSE-SU-2018:2275-1)	Nessus	SuSE Local Security Checks	high
111417	openSUSE Security Update : openssh (openSUSE-2018-765)	Nessus	SuSE Local Security Checks	high
111200	SUSE SLED12 / SLES12 Security Update : openssh (SUSE-SU-2018:1989-1)	Nessus	SuSE Local Security Checks	high
108473	EulerOS 2.0 SP2 : openssh (EulerOS-SA-2018-1069)	Nessus	Huawei Local Security Checks	high
108472	EulerOS 2.0 SP1 : openssh (EulerOS-SA-2018-1068)	Nessus	Huawei Local Security Checks	high
106407	Debian DLA-1257-1 : openssh security update	Nessus	Debian Local Security Checks	high
102751	CentOS 7 : openssh (CESA-2017:2029)	Nessus	CentOS Local Security Checks	high
102296	Oracle Linux 7 : openssh (ELSA-2017-2029)	Nessus	Oracle Linux Local Security Checks	high
102112	RHEL 7 : openssh (RHSA-2017:2029)	Nessus	Red Hat Local Security Checks	high
9855	OpenSSH 7.x < 7.4 Multiple Vulnerabilities	Nessus Network Monitor	SSH	high
96151	OpenSSH < 7.4 Multiple Vulnerabilities	Nessus	Misc.	high

Detections

Analytics

CVE-2016-10708

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Tenable Plugins

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