CVE-2015-2154 in tcpdump
Summary
by MITRE
The osi_print_cksum function in print-isoclns.c in the ethernet printer in tcpdump before 4.7.2 allows remote attackers to cause a denial of service (out-of-bounds read and crash) via a crafted (1) length, (2) offset, or (3) base pointer checksum value.
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Analysis
by VulDB Data Team • 04/16/2022
The vulnerability identified as CVE-2015-2154 represents a critical out-of-bounds read condition within the tcpdump network analysis tool's handling of OSI (Open Systems Interconnection) CLNS (Connectionless Network Service) packets. This flaw exists in the osi_print_cksum function located in the print-isoclns.c file, which processes ethernet printer data structures. The vulnerability affects tcpdump versions prior to 4.7.2 and demonstrates a classic buffer over-read scenario that can be exploited remotely by attackers who craft malicious packet data. The issue specifically manifests when the function processes checksum values with manipulated length, offset, or base pointer parameters, creating a scenario where memory access occurs beyond the allocated buffer boundaries.
The technical implementation of this vulnerability stems from inadequate input validation within the osi_print_cksum function, which fails to properly sanitize or verify the boundaries of checksum parameters before processing them. When an attacker crafts a packet with malicious length, offset, or base pointer values, the function attempts to read memory locations that are outside the intended data buffer, leading to unpredictable behavior. This flaw falls under the CWE-129 weakness category, which specifically addresses improper validation of array indices and buffer bounds checking. The function's lack of boundary validation creates an exploitable condition where arbitrary memory locations can be accessed, potentially leading to information disclosure or system instability.
From an operational perspective, this vulnerability presents a significant risk to network monitoring and security infrastructure that relies on tcpdump for packet analysis. Network administrators and security professionals who deploy tcpdump for network traffic inspection, intrusion detection, or forensic analysis are exposed to potential denial of service attacks that could disrupt critical monitoring operations. The remote exploitation capability means that an attacker located anywhere on the network can trigger this vulnerability without requiring local access or authentication. The resulting crash can lead to complete service interruption, forcing network monitoring systems to restart or become unresponsive, which can compromise network visibility and security operations. This vulnerability aligns with ATT&CK technique T1498, which covers network denial of service attacks, and demonstrates how seemingly benign network analysis tools can become attack vectors when input validation is insufficient.
The impact of this vulnerability extends beyond simple service disruption to potentially expose sensitive information through memory dumps or facilitate more sophisticated attacks. When the out-of-bounds read occurs, the function may access memory regions containing previously processed data, configuration information, or even credentials, depending on system memory layout. This information disclosure aspect increases the severity of the vulnerability beyond simple denial of service, as attackers could potentially extract sensitive data from the compromised system. Organizations using tcpdump for network security monitoring, incident response, or compliance auditing are particularly vulnerable, as these systems often run continuously and are critical to maintaining network integrity. The vulnerability's exploitation requires minimal technical expertise, making it attractive to threat actors seeking to disrupt network operations or gain unauthorized access to network monitoring infrastructure. Mitigation efforts should focus on immediate patching to tcpdump version 4.7.2 or later, along with implementing network segmentation and monitoring to detect potential exploitation attempts. Additionally, organizations should consider implementing input validation controls at network boundaries to prevent malformed packets from reaching vulnerable systems. The vulnerability serves as a reminder of the importance of robust input validation in network security tools and the critical need for regular security updates in widely deployed software components.