CVE-2006-4250 in Linux
Summary
by MITRE
Buffer overflow in man and mandb (man-db) 2.4.3 and earlier allows local users to execute arbitrary code via crafted arguments to the -H flag.
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Analysis
by VulDB Data Team • 02/02/2025
The vulnerability identified as CVE-2006-4250 represents a critical buffer overflow flaw within the man-db package version 2.4.3 and earlier, specifically affecting the man and mandb utilities. This issue arises from inadequate input validation when processing command-line arguments, particularly those supplied to the -H flag, which is used for specifying the HTML output directory. The flaw exists in the software's handling of user-supplied data without proper bounds checking, creating an exploitable condition that can be leveraged by local attackers to execute arbitrary code with the privileges of the affected process. The vulnerability demonstrates a classic buffer overflow pattern where insufficient memory allocation occurs when processing user input, allowing an attacker to overwrite adjacent memory locations and potentially gain control over the program execution flow.
The technical implementation of this vulnerability stems from the improper handling of string arguments passed to the man command's -H option, which is designed to generate HTML documentation for manual pages. When users provide overly long arguments to this flag, the application fails to validate the input length against the allocated buffer space, enabling memory corruption that can be exploited through carefully crafted input sequences. This flaw operates under the Common Weakness Enumeration category CWE-121, which classifies buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory. The vulnerability's impact is particularly severe because it affects local users who can leverage this condition to escalate privileges or execute malicious code within the context of the man command process, potentially leading to full system compromise. The exploitability of this vulnerability is enhanced by the fact that it requires no special privileges beyond local access, making it particularly dangerous in multi-user environments where local users might have access to system documentation tools.
The operational impact of CVE-2006-4250 extends beyond simple code execution, as it can be leveraged to establish persistent access or escalate privileges within affected systems. Local attackers who can execute the man command with sufficient privileges can utilize this buffer overflow to gain unauthorized access to system resources, potentially leading to data exfiltration or system disruption. The vulnerability affects systems running man-db versions up to and including 2.4.3, making it relevant to older Unix-like operating systems and distributions that have not been updated with security patches. This type of vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter, where attackers can execute arbitrary code through vulnerable command-line interfaces. The attack surface is particularly concerning because the man command is commonly used in system administration and documentation processes, making the exploitation vector readily available in normal system operations.
Mitigation strategies for CVE-2006-4250 require immediate system updates to man-db versions that have patched the buffer overflow vulnerability, specifically versions 2.4.4 and later where proper input validation has been implemented. System administrators should prioritize patching affected systems and verify that all instances of the man command are updated to prevent exploitation. Additionally, implementing proper input validation procedures and employing stack protection mechanisms such as stack canaries can help prevent similar vulnerabilities from being exploited. Security monitoring should include detection of unusual command-line arguments or patterns that might indicate exploitation attempts. Organizations should also consider implementing privilege separation techniques to limit the impact of potential exploitation, ensuring that the man command runs with minimal required privileges. The remediation process should include thorough testing of updated man-db packages to ensure that functionality remains intact while eliminating the security vulnerability. Regular security assessments and vulnerability scanning should be conducted to identify any other potentially affected applications within the system that may exhibit similar buffer overflow characteristics.