Debian update for bash

1) Command injection

EUVDB-ID: #VU5294

Risk: Critical

CVSSv3.1: 9.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:H/RL:O/RC:C]

CVE-ID: CVE-2014-7169

CWE-ID: CWE-77 - Command injection

Exploit availability: Yes

Description

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.

Mitigation

Update the affected package to version: 4.2+dfsg-0.1+deb7u3

Vulnerable software versions

Debian Linux: All versions

External links

http://ftp.gnu.org/gnu/bash/bash-4.3-patches/bash43-027

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

Yes. This vulnerability is being exploited in the wild.

2) Command injection

EUVDB-ID: #VU5295

Risk: Critical

CVSSv3.1: 9.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:H/RL:O/RC:C]

CVE-ID: CVE-2014-6271

CWE-ID: CWE-77 - Command injection

Exploit availability: Yes

Description

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.

Mitigation

Update the affected package to version: 4.2+dfsg-0.1+deb7u3

Vulnerable software versions

Debian Linux: All versions

External links

http://ftp.gnu.org/gnu/bash/bash-4.3-patches/bash43-027

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

Yes. This vulnerability is being exploited in the wild.