PT-2020-5157 · Openbsd+1 · Opensmtpd+1

Alexander E. Patrakov · Published 2020-02-24 · Updated 2022-10-08 · CVE-2020-8794

Positive Technologies (AI Summary)

CVSS v2.0

10

Critical

Base vector

AV:N/AC:L/Au:N/C:C/I:C/A:C

Name of the Vulnerable Software and Affected Versions OpenSMTPD versions prior to 6.6.4

Description The issue is related to an out-of-bounds read in the mta io function in mta session.c for multi-line replies, which can allow remote code execution. Although this affects the client side of OpenSMTPD, it is possible to attack a server because the server code launches the client code during bounce handling. The vulnerability can be exploited by sending specially crafted emails, potentially allowing attackers to take over vulnerable remote servers.

Recommendations For OpenSMTPD versions prior to 6.6.4, update to version 6.6.4 or later to resolve the issue. As a temporary workaround, consider restricting access to the mta io function in mta session.c until a patch is available. Avoid using the vulnerable code during bounce handling to minimize the risk of exploitation.

Exploit

Fix

RCE

Out of bounds Read

Weakness Enumeration

CWE-125

Related Identifiers

BDU:2020-05765

CVE-2020-8794

DSA-4634-1

USN-4294-1

USN-4875-1

Affected Products

Opensmtpd

Ubuntu

References · 46

• 🔥 https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/unix/local/opensmtpd_oob_read_lpe.rb · Exploit
• 🔥 https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/unix/smtp/opensmtpd_mail_from_rce.rb · Exploit
• 🔥 https://github.com/FiroSolutions/cve-2020-7247-exploit · Exploit
• 🔥 https://github.com/QTranspose/CVE-2020-7247-exploit · Exploit
• 🔥 https://github.com/superzerosec/cve-2020-7247 · Exploit
• 🔥 https://github.com/r0lh/CVE-2020-7247 · Exploit
• 🔥 http://packetstormsecurity.com/files/156633/OpenSMTPD-Out-Of-Bounds-Read-Local-Privilege-Escalation.html · Exploit
• 🔥 https://exploit-db.com/exploits/48140 · Exploit
• 🔥 http://openwall.com/lists/oss-security/2021/05/04/7 · Exploit
• 🔥 http://openwall.com/lists/oss-security/2020/02/26/1 · Exploit
• 🔥 https://openwall.com/lists/oss-security/2020/02/24/5 · Exploit
• 🔥 https://exploit-db.com/exploits/48185 · Exploit
• https://ubuntu.com/security/CVE-2020-8793 · Vendor Advisory
• https://osv.dev/vulnerability/DSA-4634-1 · Vendor Advisory
• https://debian.org/security/2020/dsa-4634 · Vendor Advisory