Improper input validation in Squirrelmail
CVE-2017-7692
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.
Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.322 (98.3th percentile), scored .
Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 98th percentile — 98.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.322 · newest: 0.322 · change: 0.000
Affected products
- Squirrelmail — versions 1.4.22
Weakness classification (CWE)
Public proof-of-concept exploits
References
- legalhackers.com/advisories/SquirrelMail-Exploit-Remote-Code-Exec-CVE-2017-7692… (Exploit, Third Party Advisory)
- www.securityfocus.com/bid/98067 (vdb-entry)
- openwall.com/lists/oss-security/2017/04/19/6 (Mailing List, Third Party Advisory)
- www.exploit-db.com/exploits/41910/ (exploit)
- security.gentoo.org/glsa/201709-13 (vendor-advisory)
- www.debian.org/security/2017/dsa-3852 (vendor-advisory)
- www.securitytracker.com/id/1038312 (vdb-entry)
- openwall.com/lists/oss-security/2017/04/27/1
Frequently asked questions
- What is CVE-2017-7692?
- CVE-2017-7692 is a high-severity vulnerability in Squirrelmail, classified under Improper Input Validation. CVSS score: 8.8/10. Published 2017-04-20.
- How severe is CVE-2017-7692?
- High severity. CVSS v3 base score is 8.8 out of 10.
- Is CVE-2017-7692 known to be exploited?
- 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.