Vulnerability identifier: #VU6596

Vulnerability risk: High

CVSSv3.1: 8.9 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2017-7692

CWE-ID: CWE-77

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
SquirrelMail
Web applications / Webmail solutions

Vendor: SquirrelMail Development Team

Description
The vulnerability allows a remote authenticated attacker to execute arbitrary commands on a targeted system.

The weakness exists due to insufficient escaping of user-supplied input by the escapeshellcmd() when configured with Sendmail as the email delivery transport method. A remote attacker can upload a specially crafted sendmail.cf file as an email attachment that is mishandled in a popen call, trigger vulnerability in the Deliver_SendMail.class.php with the initStream function and execute arbitrary shell commands to conduct further attacks.

Successful exploitation of the vulnerability may result in full system compromise.

Mitigation
Install update from vendor's website.

Vulnerable software versions

SquirrelMail: 1.4.22

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External links
http://sourceforge.net/p/squirrelmail/code/14649/#diff-2

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.