CVE-2005-3912 in OpenBSD
Summary
by MITRE
Format string vulnerability in miniserv.pl Perl web server in Webmin before 1.250 and Usermin before 1.180, with syslog logging enabled, allows remote attackers to cause a denial of service (crash or memory consumption) and possibly execute arbitrary code via format string specifiers in the username parameter to the login form, which is ultimately used in a syslog call. NOTE: the code execution might be associated with an issue in Perl.
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Analysis
by VulDB Data Team • 07/04/2024
The vulnerability described in CVE-2005-3912 represents a critical format string vulnerability affecting the miniserv.pl Perl web server component within Webmin and Usermin software versions prior to 1.250 and 1.180 respectively. This flaw manifests when syslog logging is enabled, creating a dangerous condition where remote attackers can manipulate the username parameter in the login form to inject format string specifiers. The technical implementation of this vulnerability stems from improper input validation and sanitization within the authentication handling process, where user-supplied data flows directly into a syslog function call without adequate protection mechanisms. The vulnerability operates at the application layer and can be classified under CWE-134, which specifically addresses the use of format strings inappropriately, making it a direct descendant of the well-known format string attack vector that has plagued many software systems over the years.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable remote code execution, making it particularly dangerous for system administrators who rely on these web management interfaces. When attackers exploit this flaw, they can cause the web server process to crash or consume excessive memory resources, effectively creating a denial of service condition that disrupts legitimate administrative access. However, the more severe implications arise from the potential for arbitrary code execution, which occurs when the format string specifiers are carefully crafted to overwrite memory locations and redirect program execution flow. The vulnerability's exploitation requires remote access to the web interface and leverages the syslog functionality to execute malicious code, representing a sophisticated attack vector that combines both denial of service and privilege escalation capabilities. This vulnerability directly maps to attack techniques outlined in the attack pattern taxonomy under the ATT&CK framework, specifically relating to privilege escalation and execution of malicious code through web application vulnerabilities.
The root cause of this vulnerability lies in the Perl programming implementation where the username parameter is passed directly to the syslog function without proper sanitization or parameter validation. This creates an environment where attackers can inject format specifiers such as %s, %d, or other format string directives that manipulate how the syslog function interprets the input data. When the syslog function processes these malformed parameters, it can lead to stack corruption, memory overwrite conditions, or even direct code execution depending on the specific implementation details and memory layout of the target system. The vulnerability is particularly concerning because it affects both Webmin and Usermin, which are widely deployed management interfaces for Unix and Linux systems, potentially impacting thousands of servers and network devices that rely on these tools for administration. The severity classification of this vulnerability is elevated due to its potential for remote code execution, which can result in complete system compromise, data theft, or further lateral movement within compromised networks. Organizations should implement immediate mitigations including updating to patched versions of Webmin and Usermin, disabling syslog logging where possible, or implementing network-level restrictions to limit access to the vulnerable login interfaces.