Vulnerability identifier: #VU5327

Vulnerability 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

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Bash
Universal components / Libraries / Scripting languages

Vendor: GNU

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 GNU Bash to version 4.3 bash43-027.

Vulnerable software versions

Bash: 1.14.0 - 4.3

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

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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.