CVE-2006-1141 in qmailadmin
Summary
by MITRE
Buffer overflow in qmailadmin.c in QmailAdmin before 1.2.10 allows remote attackers to execute arbitrary code via a long PATH_INFO environment variable.
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Analysis
by VulDB Data Team • 07/11/2019
The vulnerability described in CVE-2006-1141 represents a critical buffer overflow flaw within the QmailAdmin web administration interface, specifically within the qmailadmin.c source file. This issue affects versions of QmailAdmin prior to 1.2.10 and presents a significant security risk due to its remote exploitability. The vulnerability manifests when the application processes a maliciously crafted PATH_INFO environment variable, which is commonly used in web server environments to pass additional path information to CGI scripts. This particular implementation flaw occurs during the handling of user-supplied input within the web interface, creating an opportunity for attackers to overwrite adjacent memory locations through improper bounds checking.
The technical nature of this buffer overflow stems from inadequate input validation and memory management within the qmailadmin.c component. When a remote attacker submits a specially crafted PATH_INFO variable containing excessive data, the application fails to properly validate the length of the input before copying it into a fixed-size buffer. This classic buffer overflow condition allows the attacker to overwrite critical memory segments including return addresses, function pointers, or other control data structures. The vulnerability directly maps to CWE-121, which describes heap-based buffer overflow conditions, and CWE-122, which covers stack-based buffer overflow scenarios. The flaw enables arbitrary code execution with the privileges of the web server process, typically running as the qmail user or similar low-privilege account.
From an operational perspective, this vulnerability presents a severe risk to mail server administrators who rely on QmailAdmin for managing their email systems. The remote exploitability means that attackers can leverage this weakness without requiring physical access or local credentials, making it particularly dangerous in publicly accessible environments. Successful exploitation could result in complete compromise of the mail server, allowing attackers to execute malicious code, modify email configurations, access sensitive email data, or establish persistent backdoors. The impact extends beyond immediate system compromise as attackers could use the compromised server as a launching point for further attacks within the network infrastructure. This vulnerability aligns with ATT&CK technique T1059.007, which covers the use of CGI scripts for execution of malicious code, and T1078.004, which addresses legitimate credentials use for persistence.
The recommended mitigation strategy involves immediately upgrading to QmailAdmin version 1.2.10 or later, which contains the necessary patches to address the buffer overflow condition. Administrators should also implement network-level defenses including firewall rules that restrict access to the QmailAdmin interface to trusted IP addresses only. Additionally, input validation should be strengthened at multiple layers including web server configuration, application-level input sanitization, and runtime protections such as stack canaries or address space layout randomization. Security monitoring should be enhanced to detect unusual PATH_INFO parameter usage patterns that might indicate exploitation attempts. Organizations should also consider implementing web application firewalls to provide additional protection against malformed input attempts and conduct regular security assessments to identify similar vulnerabilities in other web applications within their infrastructure.