SB2024071024 - Ubuntu update for exim4
Published: July 10, 2024
Security Bulletin ID
SB2024071024
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Data manipulation
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Man-in-the-Middle (MitM) attack (CVE-ID: CVE-2021-38371)
CWE-ID: CWE-300 - Channel Accessible by Non-Endpoint ('Man-in-the-Middle')
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to perform MitM attack.
The vulnerability exists due to the way Exim handles concurrent STARTTLS sessions when sending out emails. A malicious server can send a response to the *next* command within the existing STARTTLS sessions and force the Exim to treat this session as trusted.
Remediation
Install update from vendor's website.