CVE-2002-0740 in SLRN
Summary
by MITRE
Buffer overflow in slrnpull for the SLRN package, when installed setuid or setgid, allows local users to gain privileges via a long -d (SPOOLDIR) argument.
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Analysis
by VulDB Data Team • 03/07/2025
The vulnerability described in CVE-2002-0740 represents a critical buffer overflow flaw within the slrnpull component of the SLRN news reader package. This issue specifically manifests when the slrnpull utility is installed with setuid or setgid permissions, creating a dangerous privilege escalation vector that can be exploited by local attackers. The vulnerability stems from inadequate input validation within the argument parsing mechanism, particularly when processing the -d (SPOOLDIR) command line option. When a local user provides an excessively long argument to this parameter, the program fails to properly bounds-check the input data before copying it into a fixed-size buffer, leading to memory corruption that can be leveraged for malicious purposes.
The technical exploitation of this buffer overflow occurs through the manipulation of the SPOOLDIR argument, which is typically used to specify the directory where news articles are stored. The flaw resides in the program's handling of command line arguments where insufficient bounds checking allows an attacker to overwrite adjacent memory locations. This memory corruption can potentially overwrite return addresses, function pointers, or other critical program state information, enabling attackers to execute arbitrary code with the elevated privileges of the slrnpull process. The setuid/setgid nature of the vulnerable binary means that any successful exploitation would grant the attacker the same privileges as the owner of the program, typically root access, making this a particularly severe vulnerability. This vulnerability directly maps to CWE-121, which describes heap-based buffer overflow conditions, and CWE-122, which covers stack-based buffer overflow conditions, both of which are common attack vectors in privilege escalation scenarios.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it creates a persistent security weakness that can be exploited repeatedly by local users without requiring network connectivity or special authentication. Attackers can leverage this flaw to gain unauthorized access to systems, potentially leading to complete system compromise, data exfiltration, or the establishment of persistent backdoors. The vulnerability affects systems running the SLRN package where slrnpull is installed with elevated permissions, making it a concern for any Unix-like system that has not properly addressed this issue. From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1068, which covers 'Exploitation for Privilege Escalation', and T1548.003, which covers 'Sudo and Sudo Caching', as it provides a method for local privilege escalation through the exploitation of setuid binaries. The attack surface is particularly concerning because it requires no network access and can be exploited by any local user with the ability to execute the slrnpull utility.
Mitigation strategies for CVE-2002-0740 must address both the immediate vulnerability and the underlying security configuration that enables it. The primary recommendation is to remove the setuid/setgid permissions from the slrnpull binary if the functionality can be maintained without elevated privileges, or to ensure that the program properly validates all input parameters before processing them. System administrators should implement input validation mechanisms that prevent overly long arguments from being processed, potentially through the use of configuration files or command line argument length limits. Additionally, the system should be updated to a patched version of the SLRN package that addresses this specific buffer overflow vulnerability. Regular security audits should verify that no other setuid/setgid binaries contain similar flaws, and the principle of least privilege should be enforced to minimize the impact of such vulnerabilities. Organizations should also consider implementing additional monitoring and logging to detect suspicious usage patterns of setuid binaries, as these vulnerabilities often result in unexpected behavior that can be flagged by security monitoring systems.