CVE-2017-7692 Information

Description

SquirrelMail 1.4.22 (and other versions before 20170427_0200-SVN) allows post-authentication remote code execution via a sendmail.cf file that is mishandled in a popen call. It’s possible to exploit this vulnerability to execute arbitrary shell commands on the remote server. The problem is in the Deliver_SendMail.class.php with the initStream function that uses escapeshellcmd() to sanitize the sendmail command before executing it. The use of escapeshellcmd() is not correct in this case since it doesn’t escape whitespaces allowing the injection of arbitrary command parameters. The problem is in -f$envelopefrom within the sendmail command line. Hence if the target server uses sendmail and SquirrelMail is configured to use it as a command-line program it’s possible to trick sendmail into using an attacker-provided configuration file that triggers the execution of an arbitrary command. For exploitation the attacker must upload a sendmail.cf file as an email attachment and inject the sendmail.cf filename with the -C option within the \Options Personal Informations Email Address\ setting.

CVSS Vector

CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Reference

http://openwall.com/lists/oss-security/2017/04/19/6 http://openwall.com/lists/oss-security/2017/04/27/1 http://www.debian.org/security/2017/dsa-3852 http://www.securityfocus.com/bid/98067 http://www.securitytracker.com/id/1038312 https://legalhackers.com/advisories/SquirrelMail-Exploit-Remote-Code-Exec-CVE-2017-7692-Vuln.html https://security.gentoo.org/glsa/201709-13 https://www.exploit-db.com/exploits/41910/

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

HIGH

Availability Impact

HIGH

Base Score

HIGH

Base Severity

8.8