CVE-2017-7701 in Wireshark
Summary
by MITRE
In Wireshark 2.2.0 to 2.2.5 and 2.0.0 to 2.0.11, the BGP dissector could go into an infinite loop, triggered by packet injection or a malformed capture file. This was addressed in epan/dissectors/packet-bgp.c by using a different integer data type.
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Analysis
by VulDB Data Team • 11/29/2022
The vulnerability identified as CVE-2017-7701 represents a critical denial of service flaw within Wireshark's BGP dissector functionality. This issue affected versions ranging from 2.2.0 through 2.2.5 and 2.0.0 through 2.0.11, creating a significant risk for network analysts and security professionals who rely on Wireshark for protocol analysis. The flaw manifested as an infinite loop condition that could be triggered through either packet injection attacks or by processing malformed capture files, fundamentally compromising the stability and usability of the network protocol analyzer.
The technical root cause of this vulnerability stems from improper handling of integer data types within the BGP dissector implementation. Specifically, the epan/dissectors/packet-bgp.c file contained code that used an inappropriate integer data type for processing BGP packet fields, leading to arithmetic overflow conditions that caused the dissector to enter an infinite loop during packet processing. This type of vulnerability falls under CWE-191, which addresses integer underflow and overflow conditions, and represents a classic example of how improper data type selection can lead to severe operational consequences. The vulnerability operates at the protocol dissector level, meaning it affects how Wireshark interprets and processes BGP protocol data, making it particularly dangerous as BGP is a critical routing protocol in internet infrastructure.
The operational impact of this vulnerability extends beyond simple service disruption to create potential security implications for network monitoring operations. When exploited through packet injection, an attacker could remotely force a Wireshark instance to enter an infinite loop, effectively causing a denial of service against network analysis tools. Similarly, when triggered through malformed capture files, the vulnerability could compromise automated network monitoring systems that rely on Wireshark for continuous packet analysis. This type of attack aligns with ATT&CK technique T1499.001, which covers network disruption attacks, and demonstrates how seemingly benign protocol analysis tools can become vectors for operational disruption. The infinite loop condition would consume excessive CPU resources and potentially cause system instability, affecting not only the local machine running Wireshark but also network monitoring infrastructure that depends on stable analysis tools.
The fix implemented by the Wireshark development team involved modifying the integer data type used in the packet-bgp.c file to prevent the overflow conditions that led to the infinite loop. This remediation approach addresses the core technical flaw by ensuring that arithmetic operations within the BGP dissector use appropriate data types that cannot overflow into causing loop conditions. The solution demonstrates proper defensive programming practices and aligns with industry best practices for preventing integer overflow vulnerabilities. Organizations using affected Wireshark versions should immediately upgrade to patched releases to eliminate this risk, as the vulnerability represents a significant threat to network monitoring operations and could be exploited to disrupt critical network analysis activities. The fix also serves as a reminder of the importance of proper data type selection in protocol analysis tools, particularly when dealing with network protocol fields that may contain variable-length data or require careful arithmetic handling.