Xen in the Linux kernel, when running a guest on a host without hardware assisted paging (HAP), allows guest users to cause a denial of service (invalid pointer dereference and hypervisor crash) via the SAHF instruction.

The remote VMware ESX / ESXi host is missing a security-related patch.
It is, therefore, affected by multiple vulnerabilities, including remote code execution vulnerabilities, in several third-party libraries :

  - COS kernel
  - cURL
  - python
  - rpm

The remote Oracle Linux 5 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2011-1212 advisory.

    - [xen] fix off-by-one shift in x86_64 __addr_ok (Laszlo Ersek) [728043 719850] {CVE-2011-2901}
    - [wireless] nl80211: check for valid SSID size in scan operation (Stanislaw Gruszka) [718154 718155]     {CVE-2011-2517}
    - [fs] proc: restrict access to /proc/PID/io (Oleg Nesterov) [716827 716828] {CVE-2011-2495}
    - [net] sunrpc: Don't hang forever on NLM unlock requests (Jeff Layton) [709546 709547] {CVE-2011-2491}

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 5 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2011:1813 advisory.

  - kernel: sctp dos (CVE-2011-2482)

  - kernel: rpc task leak after flock()ing  NFS share (CVE-2011-2491)

  - kernel: /proc/PID/io infoleak (CVE-2011-2495)

  - kernel: nl80211: missing check for valid SSID size in scan operations (CVE-2011-2517)

  - kernel: xen: x86_emulate: fix SAHF emulation (CVE-2011-2519)

  - kernel: xen: off-by-one shift in x86_64 __addr_ok() (CVE-2011-2901)

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

The kernel packages contain the Linux kernel, the core of any Linux operating system.

This update fixes the following security issues :

  - A NULL pointer dereference flaw was found in the Linux     kernel's Stream Control Transmission Protocol (SCTP)     implementation. A remote attacker could send a specially     crafted SCTP packet to a target system, resulting in a     denial of service. (CVE-2011-2482, Important)

  - A flaw in the Linux kernel's client-side NFS Lock     Manager (NLM) implementation could allow a local,     unprivileged user to cause a denial of service.
    (CVE-2011-2491, Important)

  - Buffer overflow flaws in the Linux kernel's     netlink-based wireless configuration interface     implementation could allow a local user, who has the     CAP_NET_ADMIN capability, to cause a denial of service     or escalate their privileges on systems that have an     active wireless interface. (CVE-2011-2517, Important)

  - A flaw was found in the way the Linux kernel's Xen     hypervisor implementation emulated the SAHF instruction.
    When using a fully-virtualized guest on a host that does     not use hardware assisted paging (HAP), such as those     running CPUs that do not have support for (or those that     have it disabled) Intel Extended Page Tables (EPT) or     AMD Virtualization (AMD-V) Rapid Virtualization Indexing     (RVI), a privileged guest user could trigger this flaw     to cause the hypervisor to crash. (CVE-2011-2519,     Moderate)

  - An off-by-one flaw was found in the __addr_ok() macro in     the Linux kernel's Xen hypervisor implementation when     running on 64-bit systems. A privileged guest user could     trigger this flaw to cause the hypervisor to crash.
    (CVE-2011-2901, Moderate)

  - /proc/[PID]/io is world-readable by default. Previously,     these files could be read without any further     restrictions. A local, unprivileged user could read     these files, belonging to other, possibly privileged     processes to gather confidential information, such as     the length of a password used in a process.
    (CVE-2011-2495, Low)

This update also fixes several bugs. Documentation for these bug fixes will be available shortly from the Technical Notes document linked to in the References section.

Users should upgrade to these updated packages, which contain backported patches to correct these issues, and fix the bugs noted in the Technical Notes. The system must be rebooted for this update to take effect.

a. ESX third-party update for Service Console kernel      The ESX Service Console Operating System (COS) kernel is updated to    kernel-2.6.18-274.3.1.el5 to fix multiple security issues in the    COS kernel.
     The Common Vulnerabilities and Exposures project (cve.mitre.org) has    assigned the names CVE-2011-0726, CVE-2011-1078, CVE-2011-1079,    CVE-2011-1080, CVE-2011-1093, CVE-2011-1163, CVE-2011-1166,    CVE-2011-1170, CVE-2011-1171, CVE-2011-1172, CVE-2011-1494,    CVE-2011-1495, CVE-2011-1577, CVE-2011-1763, CVE-2010-4649,    CVE-2011-0695, CVE-2011-0711, CVE-2011-1044, CVE-2011-1182,    CVE-2011-1573, CVE-2011-1576, CVE-2011-1593, CVE-2011-1745,    CVE-2011-1746, CVE-2011-1776, CVE-2011-1936, CVE-2011-2022,    CVE-2011-2213, CVE-2011-2492, CVE-2011-1780, CVE-2011-2525,    CVE-2011-2689, CVE-2011-2482, CVE-2011-2491, CVE-2011-2495,    CVE-2011-2517, CVE-2011-2519, CVE-2011-2901 to these issues.
  b. ESX third-party update for Service Console cURL RPM      The ESX Service Console (COS) curl RPM is updated to cURL-7.15.5.9    resolving a security issues.
     The Common Vulnerabilities and Exposures project (cve.mitre.org) has    assigned the name CVE-2011-2192 to this issue.
  c. ESX third-party update for Service Console nspr and nss RPMs      The ESX Service Console (COS) nspr and nss RPMs are updated to    nspr-4.8.8-1.el5_7 and nss-3.12.10-4.el5_7 respectively resolving    a security issues.
     A Certificate Authority (CA) issued fraudulent SSL certificates and    Netscape Portable Runtime (NSPR) and Network Security Services (NSS)    contain the built-in tokens of this fraudulent Certificate    Authority. This update renders all SSL certificates signed by the    fraudulent CA as untrusted for all uses.
  d. ESX third-party update for Service Console rpm RPMs      The ESX Service Console Operating System (COS) rpm packages are    updated to popt-1.10.2.3-22.el5_7.2, rpm-4.4.2.3-22.el5_7.2,    rpm-libs-4.4.2.3-22.el5_7.2 and rpm-python-4.4.2.3-22.el5_7.2    which fixes multiple security issues.
     The Common Vulnerabilities and Exposures project (cve.mitre.org) has    assigned the names CVE-2010-2059 and CVE-2011-3378 to these    issues.
  e. ESX third-party update for Service Console samba RPMs      The ESX Service Console Operating System (COS) samba packages are    updated to samba-client-3.0.33-3.29.el5_7.4,    samba-common-3.0.33-3.29.el5_7.4 and    libsmbclient-3.0.33-3.29.el5_7.4 which fixes multiple security    issues in the Samba client.
     The Common Vulnerabilities and Exposures project (cve.mitre.org) has    assigned the names CVE-2010-0547, CVE-2010-0787, CVE-2011-1678,    CVE-2011-2522 and CVE-2011-2694 to these issues.
     Note that ESX does not include the Samba Web Administration Tool    (SWAT) and therefore ESX COS is not affected by CVE-2011-2522 and    CVE-2011-2694.
  f. ESX third-party update for Service Console python package      The ESX Service Console (COS) python package is updated to    2.4.3-44 which fixes multiple security issues.
     The Common Vulnerabilities and Exposures project (cve.mitre.org) has    assigned the names CVE-2009-3720, CVE-2010-3493, CVE-2011-1015 and    CVE-2011-1521 to these issues.
  g. ESXi update to third-party component python      The python third-party library is updated to python 2.5.6 which    fixes multiple security issues.
     The Common Vulnerabilities and Exposures project (cve.mitre.org) has    assigned the names CVE-2009-3560, CVE-2009-3720, CVE-2010-1634,    CVE-2010-2089, and CVE-2011-1521 to these issues.

Updated kernel packages that fix multiple security issues and several bugs are now available for Red Hat Enterprise Linux 5.

The Red Hat Security Response Team has rated this update as having important 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.

The kernel packages contain the Linux kernel, the core of any Linux operating system.

This update fixes the following security issues :

* A NULL pointer dereference flaw was found in the Linux kernel's Stream Control Transmission Protocol (SCTP) implementation. A remote attacker could send a specially crafted SCTP packet to a target system, resulting in a denial of service. (CVE-2011-2482, Important)

* A flaw in the Linux kernel's client-side NFS Lock Manager (NLM) implementation could allow a local, unprivileged user to cause a denial of service. (CVE-2011-2491, Important)

* Buffer overflow flaws in the Linux kernel's netlink-based wireless configuration interface implementation could allow a local user, who has the CAP_NET_ADMIN capability, to cause a denial of service or escalate their privileges on systems that have an active wireless interface. (CVE-2011-2517, Important)

* A flaw was found in the way the Linux kernel's Xen hypervisor implementation emulated the SAHF instruction. When using a fully-virtualized guest on a host that does not use hardware assisted paging (HAP), such as those running CPUs that do not have support for (or those that have it disabled) Intel Extended Page Tables (EPT) or AMD Virtualization (AMD-V) Rapid Virtualization Indexing (RVI), a privileged guest user could trigger this flaw to cause the hypervisor to crash. (CVE-2011-2519, Moderate)

* An off-by-one flaw was found in the __addr_ok() macro in the Linux kernel's Xen hypervisor implementation when running on 64-bit systems.
A privileged guest user could trigger this flaw to cause the hypervisor to crash. (CVE-2011-2901, Moderate)

* /proc/[PID]/io is world-readable by default. Previously, these files could be read without any further restrictions. A local, unprivileged user could read these files, belonging to other, possibly privileged processes to gather confidential information, such as the length of a password used in a process. (CVE-2011-2495, Low)

Red Hat would like to thank Vasily Averin for reporting CVE-2011-2491, and Vasiliy Kulikov of Openwall for reporting CVE-2011-2495.

This update also fixes several bugs. Documentation for these bug fixes will be available shortly from the Technical Notes document linked to in the References section.

Users should upgrade to these updated packages, which contain backported patches to correct these issues, and fix the bugs noted in the Technical Notes. The system must be rebooted for this update to take effect.

The remote Redhat Enterprise Linux 5 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2011:1212 advisory.

  - kernel: sctp dos (CVE-2011-2482)

  - kernel: rpc task leak after flock()ing  NFS share (CVE-2011-2491)

  - kernel: /proc/PID/io infoleak (CVE-2011-2495)

  - kernel: nl80211: missing check for valid SSID size in scan operations (CVE-2011-2517)

  - kernel: xen: x86_emulate: fix SAHF emulation (CVE-2011-2519)

  - kernel: xen: off-by-one shift in x86_64 __addr_ok() (CVE-2011-2901)

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

The remote CentOS system is missing a security update which has been documented in Red Hat advisory RHSA-2011-1212.

ID	Name	Product	Family	Severity
89105	VMware ESX / ESXi Service Console and Third-Party Libraries Multiple Vulnerabilities (VMSA-2012-0001) (remote check)	Nessus	Misc.	high
68334	Oracle Linux 5 : kernel (ELSA-2011-1212)	Nessus	Oracle Linux Local Security Checks	high
64015	RHEL 5 : kernel (RHSA-2011:1813)	Nessus	Red Hat Local Security Checks	high
61132	Scientific Linux Security Update : kernel on SL5.x i386/x86_64	Nessus	Scientific Linux Local Security Checks	high
57749	VMSA-2012-0001 : VMware ESXi and ESX updates to third-party library and ESX Service Console	Nessus	VMware ESX Local Security Checks	high
56271	CentOS 5 : kernel (CESA-2011:1212)	Nessus	CentOS Local Security Checks	high
56110	RHEL 5 : kernel (RHSA-2011:1212)	Nessus	Red Hat Local Security Checks	high
801509	CentOS RHSA-2011-1212 Security Check	Log Correlation Engine	Generic	high

Detections

Analytics

CVE-2011-2519

medium

Tenable Plugins

high

high

high

high

high

high

high

high