ID: IRCNE2015012413
Date: 2015-01-28
According to “ComputerWorld”, A fault in a widely used component of most Linux distributions could allow an attacker to take remote control of a system after merely sending a malicious email.
The vulnerability, nicknamed "Ghost," is in the GNU C Library known as glibc, according to security vendor Qualys, which disclosed the issue on Tuesday as many Linux distributions released patches. Glibc is a C library that defines system calls.
Red Hat, Debian, Ubuntu and Novell have issued fixes. It is advised administrators should patch as soon as possible.
The bug first appeared in glibc in 2000. It actually was fixed on May 21, 2013, in between versions 2.17 and 2.18, Qualys CTO Wolfgang Kandek wrote in ablog post.
But at the time, the flaw wasn't recognized as a security risk, Kandek wrote. Most stable and long-term support Linux distributions weren't immediately modified, including Debian 7, Red Hat Enterprise Linux 6 and 7, CentOS 6 and 7 and Ubuntu 12.04.
Qualys found the problem during a code audit. It's unclear whether attackers exploited the vulnerability before it was found by the company.
The flaw in Glibc exposes a buffer overflow that can be triggered locally and remotely in the "gethostbyname" functions. Applications using glibc get access to a DNS resolver, which converts hostnames into an IP address, Kandek wrote.
Qualys analysts developed a proof-of-concept exploit where they sent a specially crafted email to an Exim mail server running the vulnerable version of glibc and achieved a remote shell, giving them full control.
The company is not releasing the exploit until about half of all affected machines are patched, Kandek wrote.
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