SB2014092509 - Fedora 21 update for bash

Description

This security bulletin contains information about 2 secuirty vulnerabilities.

1) Command injection (CVE-ID: CVE-2014-7169)

The vulnerability allows a remote attacker to execute arbitrary commands on the target system.

The weakness exists due to an incomplete fix related to malformed function definitions in the values of environment variables. By using multiple attack vectors (DHCP, HTTP, SIP, FTP, and SMTP) involving the ForceCommand feature in OpenSSH sshd, the mod_cgi and mod_cgid modules in the Apache HTTP Server, a remote attacker can inject and execute arbitrary commands.This vulnerability exists due to incomplete fix for vulnerability #1 (CVE-2014-6271).

Exploitation example:

env X='() { (a)=>\' bash -c "echo date"; cat echo

Successful exploitation may allow an attacker to gain complete control over vulnerable system.

Note: this vulnerability was being actively exploited.

2) Command injection (CVE-ID: CVE-2014-6271)

The vulnerability allows a remote attacker to execute arbitrary commands on the target system.

The vulnerability exists due to incorrect parsing of environment variables. A remote attacker can execute arbitrary code on the target system as demonstrated by vectors involving the ForceCommand feature in OpenSSH sshd, the mod_cgi and mod_cgid modules in the Apache HTTP Server, scripts executed by unspecified DHCP clients, and other situations in which setting the environment occurs across a privilege boundary from Bash execution.

Successful exploitation may allow an attacker to gain complete control over vulnerable system.

Exploitation example:

env x='() { :;}; echo vulnerable' bash -c "echo this is a test"

Note: this vulnerability was being actively exploited in the wild.

Remediation

Install update from vendor's website.

References

• https://bodhi.fedoraproject.org/updates/FEDORA-2014-11718