CVE-2007-6121 in Wireshark
Summary
by MITRE
Wireshark (formerly Ethereal) 0.8.16 to 0.99.6 allows remote attackers to cause a denial of service (crash) via a malformed RPC Portmap packet.
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Analysis
by VulDB Data Team • 08/01/2019
The vulnerability identified as CVE-2007-6121 affects Wireshark versions ranging from 0.8.16 through 0.99.6, representing a critical denial of service weakness that can be exploited remotely by attackers to crash the network protocol analyzer application. This flaw specifically targets the RPC Portmap packet parsing functionality within Wireshark's dissector system, which is responsible for interpreting and displaying network traffic data from various protocols including the Remote Procedure Call protocol suite. The vulnerability stems from inadequate input validation and error handling within the packet parsing logic that processes RPC Portmap messages, which are commonly used in network services for port mapping and service discovery operations.
The technical implementation of this vulnerability involves a buffer overflow condition that occurs when Wireshark attempts to parse malformed RPC Portmap packets. When processing these specially crafted packets, the application fails to properly validate the packet structure and length fields, leading to memory corruption that ultimately results in application crash. This type of vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a classic example of improper input validation in network protocol analysis tools. The attack vector is particularly concerning because it can be executed remotely without requiring authentication or specialized privileges, making it accessible to any attacker who can send network packets to a system running the vulnerable Wireshark version.
The operational impact of this vulnerability extends beyond simple service disruption, as it can severely compromise network monitoring capabilities in environments where Wireshark is used for security analysis and troubleshooting. Organizations relying on Wireshark for network traffic analysis, intrusion detection, or forensic investigations could experience complete loss of monitoring functionality when an attacker exploits this flaw. The vulnerability is particularly dangerous in enterprise environments where network analysts may be actively monitoring traffic for security events, as a successful attack could prevent detection of legitimate security incidents while simultaneously providing an attacker with a method to disrupt network operations. The flaw also creates potential for indirect impacts on network availability since network administrators may need to restart monitoring services or investigate false positives caused by the application crashes.
Mitigation strategies for this vulnerability include immediate upgrading to Wireshark version 0.99.7 or later, which contains the necessary patches to address the buffer overflow condition in RPC Portmap packet handling. Network administrators should also implement network segmentation and access controls to limit exposure of systems running Wireshark to untrusted network traffic. Additional defensive measures include deploying network-based intrusion detection systems that can identify and block malformed RPC Portmap packets before they reach the Wireshark analysis systems, as well as implementing proper network monitoring to detect when Wireshark applications crash or become unresponsive. The vulnerability demonstrates the importance of maintaining up-to-date network security tools and implementing robust input validation practices in protocol analysis applications. Organizations should also consider implementing application whitelisting policies and network access controls to prevent unauthorized systems from sending potentially malicious packets to network monitoring infrastructure. This vulnerability serves as a reminder of the critical importance of proper input validation and error handling in network security tools, as these applications often process untrusted data from network traffic and must maintain stability even when encountering malformed or malicious packets. The ATT&CK framework categorizes this type of vulnerability under defensive evasion techniques, specifically targeting application stability and availability as part of the broader network monitoring and defense evasion category.