CVE-1999-1184 in ELM
Summary
by MITRE
buffer overflow in elm 2.4 and earlier allows local users to gain privileges via a long term environmental variable.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 09/22/2024
The vulnerability identified as CVE-1999-1184 represents a classic buffer overflow flaw affecting the elm email client version 2.4 and earlier. This security weakness resides in the handling of environmental variables during program execution, specifically when processing the TERM environment variable. The vulnerability manifests as a stack-based buffer overflow that occurs when the elm client processes a specially crafted TERM variable exceeding the allocated buffer space. The flaw stems from inadequate input validation and bounds checking within the program's environmental variable parsing logic, which fails to properly sanitize user-supplied data before copying it into fixed-size buffers.
The technical exploitation of this vulnerability enables local users to execute arbitrary code with elevated privileges, potentially leading to privilege escalation from the current user context to root or system-level access. The buffer overflow occurs during the initialization phase of the elm client when it attempts to copy environmental variable values into internal buffers without proper size verification. This allows attackers to overwrite adjacent memory locations including return addresses and control data, enabling them to redirect program execution flow. The vulnerability directly maps to CWE-121, which categorizes stack-based buffer overflow conditions, and aligns with ATT&CK technique T1068, which covers privilege escalation through local exploitation of software vulnerabilities.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it can be leveraged to establish persistent access to compromised systems. Attackers can craft malicious TERM environment variables that, when processed by the vulnerable elm client, trigger the buffer overflow and execute malicious payloads. The vulnerability affects systems where elm is installed and used, particularly those running older versions where security patches have not been applied. Given that this vulnerability was discovered in 1999, it represents an older but still relevant threat vector in legacy systems or environments where software updates have not been implemented. The exploitation requires local access to the target system, making it a local privilege escalation vulnerability that can be particularly dangerous in multi-user environments where users may have legitimate access to the system but could leverage this flaw to gain unauthorized elevated privileges. Organizations should prioritize patching affected systems and implementing proper input validation measures to prevent similar buffer overflow conditions in other applications. The vulnerability also highlights the importance of secure coding practices including bounds checking, input validation, and proper memory management to prevent such exploitable conditions from being introduced into software applications.