CVE-2012-5240 in Wireshark
Summary
by MITRE
Buffer overflow in the dissect_tlv function in epan/dissectors/packet-ldp.c in the LDP dissector in Wireshark 1.8.x before 1.8.3 allows remote attackers to cause a denial of service (application crash) or possibly have unspecified other impact via a malformed packet.
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Analysis
by VulDB Data Team • 04/14/2021
The vulnerability identified as CVE-2012-5240 represents a critical buffer overflow flaw within the Layer 3 VPN protocol dissector of Wireshark, specifically affecting versions 1.8.x prior to 1.8.3. This issue resides in the dissect_tlv function located in epan/dissectors/packet-ldp.c, which is responsible for parsing Label Distribution Protocol packets used in MPLS networks. The buffer overflow occurs when the dissector processes malformed TLV (Type-Length-Value) structures within LDP packets, creating a potential attack vector that can be exploited by remote adversaries to compromise network monitoring capabilities.
The technical implementation of this vulnerability stems from inadequate input validation within the dissect_tlv function where the application fails to properly validate the length field of TLV structures before attempting to read or copy data into fixed-size buffers. When an attacker crafts a malicious LDP packet containing oversized or malformed TLV data, the function attempts to copy more data than the allocated buffer space can accommodate, resulting in memory corruption. This memory corruption manifests as application crashes during packet analysis, effectively causing a denial of service condition that prevents legitimate network monitoring operations. The vulnerability's impact extends beyond simple crashes as the buffer overflow may potentially allow for more severe consequences including arbitrary code execution, though the exact scope of potential exploitation remains unspecified in the original advisory.
From an operational perspective, this vulnerability poses significant risks to network security operations centers and forensic analysis environments that rely on Wireshark for protocol analysis. The remote nature of the attack means that adversaries can exploit this flaw without requiring physical access to the network monitoring infrastructure, making it particularly dangerous in enterprise environments where network traffic analysis is critical for security monitoring. The vulnerability affects the core functionality of Wireshark's protocol dissection capabilities, potentially compromising the integrity of network forensic investigations and security audits. Organizations using affected versions of Wireshark for network analysis, intrusion detection, or security research are at risk of experiencing complete application failures when processing malicious network traffic, leading to potential gaps in network visibility and security monitoring.
Mitigation strategies for CVE-2012-5240 primarily involve immediate patching of affected Wireshark installations to version 1.8.3 or later, which includes proper bounds checking and input validation within the dissect_tlv function. Network administrators should also implement network segmentation and traffic filtering to prevent malicious LDP packets from reaching systems running vulnerable Wireshark versions. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a classic example of improper input validation that violates secure coding practices. From an ATT&CK framework perspective, this vulnerability maps to the T1059.007 technique related to application execution through command and scripting interpreter, though the specific exploitation path focuses on denial of service rather than execution. Organizations should also consider implementing network monitoring solutions that can detect and block malformed LDP traffic patterns, as well as establishing regular vulnerability assessment procedures to identify and remediate similar issues in network analysis tools.