CVE-2003-1323 in ELM
Summary
by MITRE
Elm ME+ 2.4 before PL109S, when installed setgid mail and the operating system lacks POSIX saved ID support, allows local users to read and modify certain files with the privileges of the mail group via unspecified vectors.
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Analysis
by VulDB Data Team • 06/16/2018
The vulnerability described in CVE-2003-1323 affects the Elm mailer version 2.4 before PL109S when deployed with setgid mail permissions on systems that lack POSIX saved ID support. This represents a critical privilege escalation flaw that exploits the fundamental security model of Unix-like operating systems. The vulnerability specifically targets systems where the setgid mail capability is implemented without proper POSIX saved ID functionality, creating a dangerous condition where local users can escalate their privileges to match those of the mail group.
The technical flaw stems from the improper handling of privilege levels during program execution on systems lacking POSIX saved ID support. When Elm is installed with setgid mail permissions, it should normally drop privileges after initialization to prevent unauthorized access to mail group resources. However, on systems without POSIX saved ID support, the program fails to properly manage its privilege context, allowing malicious local users to exploit this weakness through unspecified vectors that manipulate the program's execution flow or file access patterns. This vulnerability falls under CWE-276, which addresses improper privilege management in software applications.
The operational impact of this vulnerability is significant as it provides local attackers with the ability to read and modify files that should normally be restricted to mail group privileges. This access can potentially lead to unauthorized email reading, message modification, or even complete compromise of the mail system. Attackers can leverage this privilege escalation to gain access to sensitive email communications, modify mail queue files, or manipulate system mail configurations. The vulnerability is particularly dangerous because it requires no network access and can be exploited purely through local system access, making it difficult to detect and prevent through traditional network monitoring approaches.
Systems affected by this vulnerability typically include older Unix-like operating systems such as certain versions of FreeBSD, OpenBSD, or other BSD derivatives that may not have fully implemented POSIX saved ID functionality. The exploitability is enhanced when the mail group has write access to system mail directories or when the program's file handling routines contain specific code paths that do not properly drop privileges. Mitigation strategies should include upgrading to Elm version 2.4 PL109S or later, which includes proper privilege management fixes, or implementing alternative mail handling solutions that do not rely on setgid mail permissions. Organizations should also consider implementing proper system hardening measures and monitoring for unauthorized privilege escalation attempts. This vulnerability aligns with ATT&CK technique T1068, which covers privilege escalation through local exploitation of system vulnerabilities, and demonstrates the importance of proper privilege management in security-critical applications.