Samba, the Windows interoperability suite of programs for Linux and Unix, is plagued by a serious vulnerability that can be exploited for arbitrary code execution.
The unexpected code execution flaw (CVE-2015-0240) has been found in the smbd file server daemon and it affects Samba versions 3.5.0 through 4.2.0rc4.
A malicious Samba client can exploit the security hole by sending specially crafted packets to a vulnerable Samba server. This allows an unauthenticated attacker to execute arbitrary code with root privileges.
“A malicious client could send packets that may set up the stack in such a way that the freeing of memory in a subsequent anonymous netlogon packet could allow execution of arbitrary code. This code would execute with root privileges,” Samba developers noted in an advisory.
The vulnerability has been addressed with the Samba 4.2.0rc5, 4.1.17, 4.0.25 and 3.6.25 security releases. Patches for older versions of the software have also been made available by Samba.
Security updates have been released for Red Hat, Fedora, Ubuntu, Debian, and SUSE.
“This flaw arises because of an uninitialized pointer is passed to the TALLOC_FREE() funtion. It can be exploited by calling the ServerPasswordSet RPC api on the NetLogon endpoint, by using a NULL session over IPC,” Red Hat said in a blog post.
The vulnerability was identified and reported by Richard van Eeden of Microsoft Vulnerability Research. The researcher also provided a fix for the issue.
In January, Linux distribution vendors released patches to address a critical flaw in the glibc library. The vulnerability, dubbed “Ghost,” allows remote attackers to take control of targeted systems.