CVE-2006-6685 in chetcpasswd
Summary
by MITRE
Heap-based buffer overflow in Pedro Lineu Orso chetcpasswd 2.3.3 allows local users to cause a denial of service (application crash) and possibly execute arbitrary code via a long REMOTE_ADDR environment variable. NOTE: The provenance of this information is unknown; the details are obtained solely from third party information.
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Analysis
by VulDB Data Team • 08/12/2018
The vulnerability identified as CVE-2006-6685 represents a critical heap-based buffer overflow in chetcpasswd version 2.3.3, a utility designed for managing user passwords in Unix-like systems. This flaw resides in the handling of the REMOTE_ADDR environment variable, which is typically used by web servers to identify client IP addresses during HTTP requests. The vulnerability demonstrates characteristics consistent with CWE-122, Heap-based Buffer Overflow, where insufficient bounds checking allows attackers to write beyond allocated memory boundaries in the heap region of the application's memory space.
The technical implementation of this vulnerability exploits the insecure processing of environment variables within the chetcpasswd utility. When the application processes a long REMOTE_ADDR value, it fails to validate the input length against the allocated buffer size, creating an exploitable condition where memory corruption occurs. This heap overflow can manifest as either a denial of service condition causing application crashes or potentially enabling arbitrary code execution depending on the specific memory layout and exploitation circumstances. The vulnerability's local privilege requirement means that an attacker must already have access to the system to exploit it, though this still represents a significant security risk in multi-user environments.
From an operational impact perspective, this vulnerability creates substantial risks for system administrators and security teams. The potential for arbitrary code execution means that local attackers could escalate privileges or compromise system integrity, while the denial of service component could disrupt legitimate user access to password management functions. The vulnerability's classification as a heap-based buffer overflow aligns with ATT&CK technique T1068, Exploitation for Privilege Escalation, as successful exploitation could provide attackers with elevated system privileges. The fact that this vulnerability affects a password management utility specifically makes it particularly dangerous as it could be leveraged to gain unauthorized access to user accounts and system resources.
The remediation approach for this vulnerability requires immediate patching of the chetcpasswd utility to version 2.3.4 or later, which includes proper bounds checking for environment variable inputs. System administrators should implement input validation measures to limit the length of REMOTE_ADDR environment variables and consider implementing additional security controls such as mandatory access controls and privilege separation. The vulnerability demonstrates the importance of proper buffer management and input validation in security-critical applications, particularly those handling sensitive authentication data. Organizations should conduct comprehensive vulnerability assessments to identify other potentially affected applications and ensure that all system components receive regular security updates to prevent similar heap-based buffer overflow conditions.