CVE-2012-4412

Vulnerability

An integer overflow vulnerability exists in the strcoll_l function within string/strcoll_l.c of the GNU C Library (glibc) versions 2.17 and earlier [3]. When processing a long string, this overflow leads to a heap-based buffer overflow [3]. The vulnerability is context-dependent, meaning specific conditions are required for the overflow to be triggered [3].

Exploitation

An attacker can exploit this vulnerability by providing a long string to an application that uses the affected strcoll_l function for string collation [3]. The attacker does not need any special privileges; the attack is triggered by the input data itself [3]. The exact steps involve crafting a string that, when passed to strcoll_l, causes an integer overflow in size calculations, leading to a subsequent heap buffer write beyond allocated bounds [3].

Impact

Successful exploitation can result in a denial of service (application crash) or, potentially, arbitrary code execution [3]. The impact is context-dependent, as the attacker's control over the heap-based overflow may allow for code execution with the privileges of the vulnerable process [3].

Mitigation

Ubuntu released security update USN-1991-1 on October 21, 2013, which fixed this vulnerability in eglibc (the Debian/Ubuntu variant of glibc) [3]. Users should update to the fixed version provided by their distribution. No workarounds other than applying the patch are mentioned in the references. For glibc versions prior to 2.18, the fix is incorporated by updating to that release or later [3].