CVE-2002-2048 in PFinger
Summary
by MITRE
Buffer overflow in PFinger 0.7.8 client allows remote attackers to execute arbitrary code via a long query value passed to the (1) finger program, (2) -l, (3) -d, and (4) -t options. NOTE: if PFinger is not setuid or setgid, then this issue would not cross privilege boundaries and would not be considered a vulnerability.
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Analysis
by VulDB Data Team • 06/11/2018
The vulnerability identified as CVE-2002-2048 represents a critical buffer overflow flaw in PFinger version 0.7.8 client software that enables remote attackers to execute arbitrary code on affected systems. This vulnerability specifically targets the finger program implementation within PFinger and affects multiple command-line options including -l, -d, and -t parameters. The core issue arises from insufficient input validation and bounds checking when processing user-supplied query values, creating an exploitable condition where maliciously crafted input can overwrite adjacent memory locations beyond the allocated buffer space.
The technical implementation of this vulnerability stems from the improper handling of user input within the PFinger client application. When the finger program processes command-line arguments containing excessively long query strings, the application fails to properly validate the input length before copying data into fixed-size buffers. This classic buffer overflow condition allows attackers to overwrite return addresses, stack canaries, or other critical program variables, potentially enabling code execution with the privileges of the running process. The vulnerability is particularly concerning because it affects multiple operational modes of the finger program, expanding the attack surface and increasing the likelihood of successful exploitation.
From an operational perspective, the impact of this vulnerability extends beyond simple code execution to potentially compromise entire system security postures. The vulnerability's remote exploitability means that attackers can leverage it without requiring local system access, making it particularly dangerous in networked environments. The attack vector involves sending specially crafted long query values through the finger protocol, which when processed by the vulnerable PFinger client, triggers the buffer overflow condition. This type of vulnerability directly relates to CWE-121, which describes heap-based buffer overflow conditions, and aligns with ATT&CK technique T1059.007 for command and scripting interpreter. The privilege escalation aspect becomes significant when PFinger is configured with setuid or setgid permissions, as exploitation could allow attackers to gain elevated system privileges.
The security implications of CVE-2002-2048 extend to broader network security practices and system hardening requirements. Organizations running vulnerable PFinger installations face potential compromise of their finger service functionality and overall system integrity. The vulnerability demonstrates the importance of proper input validation and the dangers of legacy software configurations that may retain unnecessary privileged execution capabilities. System administrators should consider immediate remediation through software updates or patching, while also implementing network segmentation to limit exposure of finger services. The vulnerability's classification as a remote code execution flaw underscores the necessity of regular security assessments and vulnerability management processes to identify and address similar issues in other network services and applications. Organizations must also evaluate their current setuid/setgid configurations to ensure they align with security best practices and minimize potential attack vectors that could lead to privilege escalation and system compromise.