USN-2985-1: GNU C Library vulnerabilities

25 May 2016

eglibc, glibc vulnerabilities

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

  • Ubuntu 15.10
  • Ubuntu 14.04 LTS
  • Ubuntu 12.04 LTS

Summary

Several security issues were fixed in the GNU C Library.

Software Description

  • glibc - GNU C Library
  • eglibc - GNU C Library

Details

Martin Carpenter discovered that pt_chown in the GNU C Library did not properly check permissions for tty files. A local attacker could use this to gain administrative privileges or expose sensitive information. (CVE-2013-2207, CVE-2016-2856)

Robin Hack discovered that the Name Service Switch (NSS) implementation in the GNU C Library did not properly manage its file descriptors. An attacker could use this to cause a denial of service (infinite loop). (CVE-2014-8121)

Joseph Myers discovered that the GNU C Library did not properly handle long arguments to functions returning a representation of Not a Number (NaN). An attacker could use this to cause a denial of service (stack exhaustion leading to an application crash) or possibly execute arbitrary code. (CVE-2014-9761)

Arjun Shankar discovered that in certain situations the nss_dns code in the GNU C Library did not properly account buffer sizes when passed an unaligned buffer. An attacker could use this to cause a denial of service or possibly execute arbitrary code. (CVE-2015-1781)

Sumit Bose and Lukas Slebodnik discovered that the Name Service Switch (NSS) implementation in the GNU C Library did not handle long lines in the files databases correctly. A local attacker could use this to cause a denial of service (application crash) or possibly execute arbitrary code. (CVE-2015-5277)

Adam Nielsen discovered that the strftime function in the GNU C Library did not properly handle out-of-range argument data. An attacker could use this to cause a denial of service (application crash) or possibly expose sensitive information. (CVE-2015-8776)

Hector Marco and Ismael Ripoll discovered that the GNU C Library allowed the pointer-guarding protection mechanism to be disabled by honoring the LD_POINTER_GUARD environment variable across privilege boundaries. A local attacker could use this to exploit an existing vulnerability more easily. (CVE-2015-8777)

Szabolcs Nagy discovered that the hcreate functions in the GNU C Library did not properly check its size argument, leading to an integer overflow. An attacker could use to cause a denial of service (application crash) or possibly execute arbitrary code. (CVE-2015-8778)

Maksymilian Arciemowicz discovered a stack-based buffer overflow in the catopen function in the GNU C Library when handling long catalog names. An attacker could use this to cause a denial of service (application crash) or possibly execute arbitrary code. (CVE-2015-8779)

Florian Weimer discovered that the getnetbyname implementation in the GNU C Library did not properly handle long names passed as arguments. An attacker could use to cause a denial of service (stack exhaustion leading to an application crash). (CVE-2016-3075)

Update instructions

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

Ubuntu 15.10
libc6 - 2.21-0ubuntu4.2
libc6-dev - 2.21-0ubuntu4.2
Ubuntu 14.04 LTS
libc6 - 2.19-0ubuntu6.8
libc6-dev - 2.19-0ubuntu6.8
Ubuntu 12.04 LTS
libc6 - 2.15-0ubuntu10.14
libc6-dev - 2.15-0ubuntu10.14

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

After a standard system update you need to reboot your computer to make all the necessary changes.

References