Exim Out-of-bounds Write Vulnerability
Exim contains an out-of-bounds write vulnerability which can allow for remote code execution.
A remote attacker, without authentication, can achieve full data confidentiality loss, arbitrary modification of data, complete denial of service or system unavailability. Federal agencies are required to remediate by 2022-03-17 under CISA BOD 22-01.
This is a Out-of-bounds Write (CWE-787) vulnerability in Exim Exim Internet Mailer. Exim 4.92 through 4.92.2 allows remote code execution, a different vulnerability than CVE-2019-15846. There is a heap-based buffer overflow in string_vformat in string.c involving a long EHLO command. Exploitation requires remote network access, low attack complexity, no authentication required, and no user interaction required.
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Phishing link
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Malicious file
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Server compromised
Probably yes if any of these apply:
Active exploitation documented in the wild. Threat-research write-up: http://www.openwall.com/lists/oss-security/2019/09/28/1
Manual remediation steps
Apply the Vendor Patch
This vulnerability is in the CISA Known Exploited Vulnerabilities catalog — apply the vendor's security update as soon as possible.
CISA required action: Apply updates per vendor instructions.
References
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References