CVE-1999-1220 in Majordomo
Summary
by MITRE
Majordomo 1.94.3 and earlier allows remote attackers to execute arbitrary commands when the advertise or noadvertise directive is used in a configuration file, via shell metacharacters in the Reply-To header.
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Analysis
by VulDB Data Team • 04/17/2026
The vulnerability identified as CVE-1999-1220 affects Majordomo mailing list management software version 1.94.3 and earlier, representing a critical command injection flaw that enables remote attackers to execute arbitrary system commands. This vulnerability stems from improper input validation within the software's handling of configuration directives, specifically when processing the advertise or noadvertise commands in configuration files. The flaw occurs when the system processes email headers, particularly the Reply-To field, without adequate sanitization of shell metacharacters that may be present in user-supplied input.
The technical implementation of this vulnerability exploits a classic command injection weakness where untrusted data flows directly into shell execution contexts. When Majordomo processes mailing list configuration files, it interprets certain directives by executing system commands that incorporate data from email headers. The Reply-To header, which typically contains email addresses, becomes a vector for attack when it contains shell metacharacters such as semicolons, ampersands, or backticks that are interpreted by the underlying shell. This behavior aligns with CWE-78, which describes improper neutralization of special elements used in OS commands, and represents a fundamental flaw in input sanitization practices.
The operational impact of this vulnerability extends beyond simple remote code execution, as it provides attackers with full system access to the affected server. An attacker could leverage this vulnerability to gain shell access, escalate privileges, modify or delete mailing list configurations, compromise other system resources, or establish persistent backdoors. The remote nature of the attack means that exploitation does not require local system access, making it particularly dangerous for systems hosting public mailing lists or those accessible over the internet. This vulnerability directly maps to attack techniques described in the MITRE ATT&CK framework under T1059.001 for command and scripting interpreter and T1078.004 for valid accounts, as it allows adversaries to execute commands through legitimate system interfaces.
Mitigation strategies for CVE-1999-1220 should focus on immediate patching of affected Majordomo installations to versions that properly sanitize input before shell command execution. Organizations should implement strict input validation for all email headers, particularly those used in configuration processing, and consider implementing web application firewalls or proxy solutions that can filter out potentially malicious shell metacharacters. Network segmentation and access controls should be enforced to limit exposure of vulnerable systems, while regular security audits should verify that no unauthorized modifications have occurred. Additionally, system monitoring should be enhanced to detect unusual command execution patterns that may indicate exploitation attempts. The vulnerability underscores the importance of defense in depth strategies and proper input validation as fundamental security practices that should be implemented across all system components processing untrusted data.