CVE-2006-0196 in Serial line sniffer
Summary
by MITRE
Unspecified vulnerability in Serial line sniffer (aka slsnif) 0.4.4 allows local users to gain privileges via a long value of the HOME environment variable, possibly because of a buffer overflow.
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Analysis
by VulDB Data Team • 08/04/2017
The vulnerability identified as CVE-2006-0196 resides within the Serial line sniffer utility known as slsnif version 0.4.4, representing a critical security flaw that enables local attackers to escalate their privileges through manipulation of the HOME environment variable. This issue demonstrates the classic pattern of buffer overflow vulnerabilities that have plagued numerous network and system utilities throughout the early 2000s era of software development. The vulnerability specifically manifests when the slsnif utility processes a malformed HOME environment variable value, suggesting that the application fails to properly validate or constrain input lengths before performing operations that may lead to memory corruption.
The technical mechanism behind this vulnerability aligns with common buffer overflow patterns where insufficient bounds checking allows an attacker to overwrite adjacent memory locations within the process address space. When the slsnif utility initializes and reads the HOME environment variable, it appears to store this value in a fixed-size buffer without adequate validation of the input length. This flaw creates an exploitable condition where a carefully crafted long HOME variable value can overwrite critical memory segments including return addresses, stack canaries, or other control data structures that govern program execution flow. The vulnerability's classification as a local privilege escalation issue indicates that while exploitation requires local system access, the successful exploitation can result in elevated privileges that may allow full system compromise.
From an operational perspective, this vulnerability presents a significant risk to systems where slsnif is installed and actively used, particularly in environments where local users might not be fully trusted or where system administrators have not properly secured their local user environments. The attack vector is relatively straightforward requiring only that a local user manipulate their environment variables to trigger the overflow condition, making this vulnerability particularly dangerous in multi-user systems or shared computing environments. The impact extends beyond simple privilege escalation as successful exploitation could potentially provide attackers with the ability to execute arbitrary code with elevated privileges, access sensitive system information, or establish persistent access mechanisms.
The vulnerability maps directly to CWE-121, which describes the classic stack-based buffer overflow condition, and also aligns with ATT&CK technique T1068, which covers 'Exploitation for Privilege Escalation' through the use of local exploits. Organizations should immediately implement mitigations including updating to a patched version of slsnif if available, or alternatively implementing environment variable restrictions that prevent overly long values from being processed by the application. System administrators should also consider implementing monitoring for unusual environment variable patterns and conduct thorough security audits of all system utilities that process environment variables. Additionally, the vulnerability highlights the importance of proper input validation and bounds checking in all system utilities, particularly those that may be invoked with elevated privileges or operate in multi-user environments where input sanitization becomes critical for maintaining system integrity and preventing exploitation by malicious users.