CVE-2005-1100 in GLD
Summary
by MITRE
Format string vulnerability in the ErrorLog function in cnf.c in Greylisting daemon (GLD) 1.3 and 1.4 allows remote attackers to execute arbitrary code via format string specifiers in data that is passed directly to syslog.
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Analysis
by VulDB Data Team • 01/02/2025
The CVE-2005-1100 vulnerability represents a critical format string flaw in the Greylisting daemon (GLD) version 1.3 and 1.4, specifically within the ErrorLog function located in the cnf.c source file. This vulnerability arises from improper handling of user-supplied input that is directly passed to the syslog function without adequate sanitization or formatting controls. The flaw enables remote attackers to manipulate the format string parameters, potentially leading to arbitrary code execution on the affected system. The vulnerability is particularly dangerous because it allows attackers to inject malicious format specifiers that can trigger buffer overflows, stack corruption, or information disclosure attacks.
The technical implementation of this vulnerability stems from the insecure use of printf-style functions in the ErrorLog function where external data is directly incorporated into the syslog call without proper validation or escaping. When the daemon processes incoming data that contains format specifiers such as %s, %d, or %x, these characters are interpreted by the syslog function as formatting directives rather than literal text. This creates an opportunity for attackers to craft malicious input that can cause the application to read from arbitrary memory locations or write data to specific memory addresses. The vulnerability aligns with CWE-134 which specifically addresses the use of format strings with user-supplied data, making it a classic example of improper input validation in security-critical code paths.
From an operational perspective, this vulnerability presents significant risk to systems running the affected Greylisting daemon versions, as it allows remote code execution without requiring authentication or prior access to the system. Attackers can exploit this weakness to gain unauthorized control over the daemon process, potentially leading to complete system compromise. The impact extends beyond immediate code execution to include information disclosure, where attackers can read sensitive memory contents, and denial of service conditions that can disrupt legitimate email filtering operations. This vulnerability particularly affects email server environments where Greylisting daemon is deployed as a security mechanism to filter spam, making the attack surface more critical for network administrators.
The exploitation of CVE-2005-1100 can be mapped to several ATT&CK techniques including T1059 for command and script injection, T1068 for exploit for privilege escalation, and T1046 for network service scanning. Organizations should implement immediate mitigations including updating to patched versions of the Greylisting daemon, applying input validation measures to sanitize all data passed to logging functions, and implementing network segmentation to limit exposure. The recommended approach includes disabling the vulnerable ErrorLog function or implementing proper format string handling through functions like snprintf or vsnprintf that prevent buffer overflows. Additionally, monitoring for unusual syslog entries and implementing intrusion detection systems can help identify exploitation attempts, while regular security audits of legacy software components should be conducted to identify similar vulnerabilities in other system components.