========================================================================== Ubuntu Security Notice USN-1188-1 August 09, 2011 ecryptfs-utils vulnerabilities ========================================================================== A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 11.04 - Ubuntu 10.10 - Ubuntu 10.04 LTS Summary: eCryptfs could be tricked into mounting and unmounting arbitrary locations, and possibly disclose confidential information. Software Description: - ecryptfs-utils: ecryptfs cryptographic filesystem (utilities) Details: Vasiliy Kulikov and Dan Rosenberg discovered that eCryptfs incorrectly validated permissions on the requested mountpoint. A local attacker could use this flaw to mount to arbitrary locations, leading to privilege escalation. (CVE-2011-1831) Vasiliy Kulikov and Dan Rosenberg discovered that eCryptfs incorrectly validated permissions on the requested mountpoint. A local attacker could use this flaw to unmount to arbitrary locations, leading to a denial of service. (CVE-2011-1832) Vasiliy Kulikov and Dan Rosenberg discovered that eCryptfs incorrectly validated permissions on the requested source directory. A local attacker could use this flaw to mount an arbitrary directory, possibly leading to information disclosure. A pending kernel update will provide the other half of the fix for this issue. (CVE-2011-1833) Dan Rosenberg and Marc Deslauriers discovered that eCryptfs incorrectly handled modifications to the mtab file when an error occurs. A local attacker could use this flaw to corrupt the mtab file, and possibly unmount arbitrary locations, leading to a denial of service. (CVE-2011-1834) Marc Deslauriers discovered that eCryptfs incorrectly handled keys when setting up an encrypted private directory. A local attacker could use this flaw to manipulate keys during creation of a new user. (CVE-2011-1835) Marc Deslauriers discovered that eCryptfs incorrectly handled permissions during recovery. A local attacker could use this flaw to possibly access another user's data during the recovery process. This issue only applied to Ubuntu 11.04. (CVE-2011-1836) Vasiliy Kulikov discovered that eCryptfs incorrectly handled lock counters. A local attacker could use this flaw to possibly overwrite arbitrary files. The default symlink restrictions in Ubuntu 10.10 and 11.04 should protect against this issue. (CVE-2011-1837) Update instructions: The problem can be corrected by updating your system to the following package versions: Ubuntu 11.04: ecryptfs-utils 87-0ubuntu1.1 Ubuntu 10.10: ecryptfs-utils 83-0ubuntu3.2.10.10.1 Ubuntu 10.04 LTS: ecryptfs-utils 83-0ubuntu3.2.10.04.1 In general, a standard system update will make all the necessary changes. References: http://www.ubuntu.com/usn/usn-1188-1 CVE-2011-1831, CVE-2011-1832, CVE-2011-1833, CVE-2011-1834, CVE-2011-1835, CVE-2011-1836, CVE-2011-1837 Package Information: https://launchpad.net/ubuntu/+source/ecryptfs-utils/87-0ubuntu1.1 https://launchpad.net/ubuntu/+source/ecryptfs-utils/83-0ubuntu3.2.10.10.1 https://launchpad.net/ubuntu/+source/ecryptfs-utils/83-0ubuntu3.2.10.04.1