CVE-2015-1781

Desbordamiento de buffer en gethostbyname_r y otras funciones NSS no especificadas en la librería C de GNU (también conocida como glibc o libc6) en versiones anteriores a 2.22, permite a atacantes dependientes del contexto provocar una denegación de servicio (caída) o ejecutar código arbitrario a través de una respuesta DNS manipulada, lo que desencadena una llamada con un buffer incorrectamente alineado.

A buffer overflow flaw was found in the way glibc's gethostbyname_r() and other related functions computed the size of a buffer when passed a misaligned buffer as input. An attacker able to make an application call any of these functions with a misaligned buffer could use this flaw to crash the application or, potentially, execute arbitrary code with the permissions of the user running the application.

The glibc packages provide the standard C libraries, POSIX thread libraries, standard math libraries, and the Name Server Caching Daemon used by multiple programs on the system. Without these libraries, the Linux system cannot function correctly. It was discovered that the nss_files backend for the Name Service Switch in glibc would return incorrect data to applications or corrupt the heap. A local attacker could potentially use this flaw to execute arbitrary code on the system. It was discovered that, under certain circumstances, glibc's getaddrinfo() function would send DNS queries to random file descriptors. An attacker could potentially use this flaw to send DNS queries to unintended recipients, resulting in information disclosure or data loss due to the application encountering corrupted data.