CVE-2007-6439 in Wireshark
Summary
by MITRE
Wireshark (formerly Ethereal) 0.99.6 allows remote attackers to cause a denial of service (infinite or large loop) via the (1) IPv6 or (2) USB dissector, which can trigger resource consumption or a crash. NOTE: this identifier originally included Firebird/Interbase, but it is already covered by CVE-2007-6116. The DCP ETSI issue is already covered by CVE-2007-6119.
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Analysis
by VulDB Data Team • 08/02/2019
CVE-2007-6439 represents a critical denial of service vulnerability affecting Wireshark version 0.99.6 that demonstrates the dangers of improper input validation in network protocol dissectors. This vulnerability exists within the IPv6 and USB dissectors of the network analysis tool, where maliciously crafted network packets can trigger infinite loops or excessively large processing loops that consume system resources or cause application crashes. The flaw stems from inadequate boundary checking and loop termination conditions in the dissector code, allowing attackers to craft specially formatted packets that cause the application to enter into computationally expensive processing states. This vulnerability directly maps to CWE-835, which addresses the weakness of an infinite loop in software implementations, and aligns with ATT&CK technique T1499.004 for network denial of service attacks. The impact extends beyond simple resource exhaustion as the vulnerability can be exploited remotely without authentication, making it particularly dangerous in network monitoring environments where Wireshark is commonly deployed.
The technical implementation of this vulnerability occurs when Wireshark processes network traffic through its dissectors, which are responsible for parsing and interpreting protocol data. In the case of the IPv6 dissector, malformed IPv6 packet structures can cause the application to enter recursive or iterative processing loops when attempting to parse extension headers or other IPv6-specific fields. Similarly, the USB dissector contains logic flaws that can trigger infinite loops when processing USB protocol data structures. These issues are particularly concerning because they occur during the normal packet processing flow, meaning that any network monitoring system running vulnerable Wireshark versions could be compromised simply by capturing traffic containing maliciously crafted packets. The vulnerability affects both the IPv6 dissector and USB dissector, indicating that the root cause likely involves a common code pattern or architectural flaw in how these dissectors handle certain packet structures.
Operational impact of CVE-2007-6439 extends far beyond individual system compromise, as it represents a significant threat to network monitoring infrastructure and security operations centers that rely on Wireshark for traffic analysis. When exploited, this vulnerability can cause complete system downtime or resource exhaustion, potentially affecting network availability and security monitoring capabilities. The remote exploitation capability means that attackers can target systems without physical access or network privileges, making it particularly dangerous in enterprise environments where network monitoring tools are widely deployed. Security teams responsible for network traffic analysis and incident response may find their monitoring tools become unavailable during security incidents, potentially masking actual network threats. The vulnerability also creates opportunities for attackers to perform persistent denial of service attacks against network monitoring infrastructure, undermining the integrity of network security operations. Additionally, the crash conditions can potentially be exploited for more advanced attacks if the application's memory management is not properly handled during the crash scenario.
Mitigation strategies for CVE-2007-6439 focus primarily on immediate version updates and operational hardening measures. The most effective solution is upgrading to Wireshark version 0.99.7 or later, which includes patches specifically addressing the infinite loop conditions in both dissectors. Organizations should also implement network segmentation and access controls to limit exposure of vulnerable Wireshark installations to untrusted networks. Network administrators should consider implementing traffic filtering rules to prevent potentially malicious packets from reaching systems running vulnerable versions. Additionally, monitoring systems should be configured to detect unusual resource consumption patterns that might indicate exploitation attempts. The vulnerability highlights the importance of input validation and boundary checking in protocol parsing code, with recommendations to implement defensive programming practices including loop limits, timeout mechanisms, and proper error handling in dissector implementations. Security teams should also consider implementing network traffic analysis tools that provide better monitoring capabilities for detecting potential exploitation attempts and ensuring continued availability of network monitoring infrastructure.