Ubuntu update for Bash

Published: 2015-09-27

Risk	Critical
Patch available	YES
Number of vulnerabilities	2
CVE-ID	CVE-2014-7186 CVE-2014-7187
CWE-ID	CWE-119 CWE-193
Exploitation vector	Network
Public exploit	Vulnerability #1 is being exploited in the wild. Vulnerability #2 is being exploited in the wild.
Vulnerable software Subscribe	Ubuntu Operating systems & Components / Operating system
Vendor	Canonical Ltd.

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) Memory corruption

EUVDB-ID: #VU5327

Risk: Critical

CVSSv3.1: 9.3 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:F/RL:O/RC:C]

CVE-ID: CVE-2014-7186

CWE-ID: CWE-119 - Memory corruption

Exploit availability: Yes

Description

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

The weakness exists due to out-of-bounds memory access while handling multiple "<<EOF" declarations. A remote attacker can trigger memory corruption and execute arbitrary code.

Exploitation example:

bash -c 'true <<EOF <<EOF <<EOF <<EOF <<EOF <<EOF <<EOF <<EOF <<EOF <<EOF <<EOF <<EOF <<EOF <<EOF' ||  echo "CVE-2014-7186 vulnerable, redir_stack"

Successful exploitation results in arbitrary code execution on the vulnerable system.

Note: this vulnerability was being actively exploited.

Mitigation

Update the affected packages

Ubuntu 14.04 LTS:

bash 4.3-7ubuntu1.4

Ubuntu 12.04 LTS:

bash 4.2-2ubuntu2.5

Ubuntu 10.04 LTS:

bash 4.1-2ubuntu3.4

Vulnerable software versions

Ubuntu: 12.04 - 14.04

External links

http://www.ubuntu.com/usn/usn-2364-1/

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?

No. We are not aware of malware exploiting this vulnerability. However, a fully functional exploit for this vulnerability is available.

2) Off-by-one error

EUVDB-ID: #VU5328