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Vulnerability of Xen: privilege escalation via libelf

Synthesis of the vulnerability 

An attacker, who is administrator in a PV/HVM kernel, can load a malicious kernel/firmware, to corrupt the memory of libelf of Xen, in order to escalate his privileges on the host system.
Vulnerable systems: XenDesktop, XenServer, Debian, Fedora, SUSE Linux Enterprise Desktop, SLES, Unix (platform) ~ not comprehensive.
Severity of this threat: 2/4.
Number of vulnerabilities in this bulletin: 3.
Creation date: 05/06/2013.
Références of this weakness: BID-60701, BID-60702, BID-60703, CERTA-2013-AVI-380, CERTA-2013-AVI-496, CTX138058, CTX138633, CVE-2013-2194, CVE-2013-2195, CVE-2013-2196, DSA-3006-1, FEDORA-2013-10929, FEDORA-2013-10941, SUSE-SU-2013:1314-1, SUSE-SU-2014:0411-1, SUSE-SU-2014:0446-1, SUSE-SU-2014:0470-1, VIGILANCE-VUL-12914, XSA-55.

Description of the vulnerability 

The Xen product uses libelf, in order to analyze ELF data of the kernel/firmware.

However, libelf is impacted by several integer overflows and memory corruptions.

An attacker, who is administrator in a PV/HVM kernel, can therefore load a malicious kernel/firmware, to corrupt the memory of libelf of Xen, in order to escalate his privileges on the host system.
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This cybersecurity threat impacts software or systems such as XenDesktop, XenServer, Debian, Fedora, SUSE Linux Enterprise Desktop, SLES, Unix (platform) ~ not comprehensive.

Our Vigil@nce team determined that the severity of this computer threat note is medium.

The trust level is of type confirmed by the editor, with an origin of user shell.

This bulletin is about 3 vulnerabilities.

An attacker with a expert ability can exploit this security threat.

Solutions for this threat 

Xen: version 4.2.3.
The version 4.2.3 is fixed:
  http://xenbits.xen.org/gitweb/?p=xen.git;a=shortlog;h=refs/heads/stable-4.2
  http://www.xenproject.org/downloads/xen-archives/supported-xen-42-series/xen-423.html

Xen: version 4.1.6.1.
The version 4.1.6.1 is fixed:
  http://www.xenproject.org/downloads/xen-archives/supported-xen-41-series/xen-4161.html
  http://xenbits.xen.org/gitweb/?p=xen.git;a=shortlog;h=refs/heads/stable-4.1

Xen: patch for libelf.
A patch is available:
  http://lists.xen.org/archives/html/xen-devel/2013-06/msg00223.html

Citrix XenClient XT: versions 2.1.3 and 3.1.4.
Versions 2.1.3 and 3.1.4 are fixed:
  http://www.citrix.com/downloads/xenclient/product-software/xenclient-xt-213.html
  http://www.citrix.com/downloads/xenclient/product-software/xenclient-xt-314.html

Citrix XenServer: patch for libelf.
Patches are avalable for each versions of XenServer:
  XenServer 6.2.0: CTX138349 Hotfix XS62E002
  XenServer 6.1.0: CTX138038 Hotfix XS61E024
  XenServer 6.0.2: CTX138036 - Hotfix XS602E025, or CTX138037 - Hotfix XS602ECC006 for the certified version.
  XenServer 6.0: CTX138035 - Hotfix XS60E033
  XenServer 5.6 Service Pack 2: CTX138345 - Hotfix XS56ESP2032
  XenServer 5.6 Feature Pack 1: CTX138344 - Hotfix XS56EFP1020
  XenServer 5.6: CTX138031 - Hotfix XS56E020, or CTX138343 - Hotfix XS56E021 for the certified version
  XenServer 5.0 Update 3: CTX138341 - Hotfix XS50EU3018

Debian: new xen packages.
New packages are available:
  Debian 7: xen 4.1.4-3+deb7u2

Fedora: new xen packages.
New packages are available:
  Fedora 18 : xen-4.2.2-7.fc18
  Fedora 17 : xen-4.1.5-6.fc17

SUSE LE 10: new xen packages (20/03/2014).
New packages are available:
  SUSE LE 10: xen 3.2.3_17040_46-0.7.1

SUSE LE 11: new xen packages.
New packages are available:
  xen-4.2.2_06-0.7.1

SUSE LE 11 SP1: new xen packages.
New packages are available:
  SUSE LE 11: xen 4.0.3_21548_16-0.5.1
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