USN-1009-2: GNU C Library vulnerability

Ubuntu Security Notice USN-1009-2

11th January, 2011

eglibc, glibc vulnerability

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 10.10
  • Ubuntu 10.04 LTS
  • Ubuntu 9.10
  • Ubuntu 8.04 LTS

Summary

Privilege escalation via loading of libraries via RPATH DSTs with setuid programs.

Software description

  • eglibc - Embedded GNU C Library: sources
  • glibc - GNU C Library: Documentation

Details

USN-1009-1 fixed vulnerabilities in the GNU C library. Colin Watson
discovered that the fixes were incomplete and introduced flaws with
setuid programs loading libraries that used dynamic string tokens in their
RPATH. If the "man" program was installed setuid, a local attacker could
exploit this to gain "man" user privileges, potentially leading to further
privilege escalations. Default Ubuntu installations were not affected.

Original advisory details:

Tavis Ormandy discovered multiple flaws in the GNU C Library's handling
of the LD_AUDIT environment variable when running a privileged binary. A
local attacker could exploit this to gain root privileges. (CVE-2010-3847,
CVE-2010-3856)

Update instructions

The problem can be corrected by updating your system to the following package version:

Ubuntu 10.10:
libc6 2.12.1-0ubuntu10.1
Ubuntu 10.04 LTS:
libc6 2.11.1-0ubuntu7.7
Ubuntu 9.10:
libc6 2.10.1-0ubuntu19
Ubuntu 8.04 LTS:
libc6 2.7-10ubuntu8

To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.

In general, a standard system update will make all the necessary changes.

References

LP: 701783