CVE-2015-8717 in Wireshark
Summary
by MITRE
The dissect_sdp function in epan/dissectors/packet-sdp.c in the SDP dissector in Wireshark 1.12.x before 1.12.9 does not prevent use of a negative media count, which allows remote attackers to cause a denial of service (application crash) via a crafted packet.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 07/02/2022
The vulnerability identified as CVE-2015-8717 resides within the Session Description Protocol (SDP) dissector component of Wireshark, specifically in the dissect_sdp function located at epan/dissectors/packet-sdp.c. This flaw affects Wireshark versions 1.12.x prior to 1.12.9, representing a critical denial of service vulnerability that can be exploited remotely by attackers who craft malicious SDP packets. The issue stems from inadequate input validation within the protocol dissector, which fails to properly handle malformed media count values.
The technical flaw manifests when the dissect_sdp function processes SDP packets containing negative media count values. In normal operation, SDP packets should contain non-negative integer values for media count fields, as specified in RFC 4175 and related session description protocol standards. However, the Wireshark dissector does not validate that the media count field contains a valid non-negative value, allowing attackers to inject negative integers that cause the application to crash during packet processing. This occurs because the dissector attempts to use the negative value in array indexing or loop control structures without proper bounds checking, leading to memory corruption and subsequent application termination.
The operational impact of this vulnerability extends beyond simple denial of service, as it can be exploited in network monitoring and forensic analysis environments where Wireshark is commonly deployed. Attackers can remotely trigger crashes on systems running vulnerable versions of Wireshark, potentially disrupting network troubleshooting, security analysis, and incident response activities. The vulnerability is particularly concerning in environments where automated network monitoring systems rely on Wireshark for packet analysis, as a single malicious packet could cause system-wide outages. This represents a classic example of a buffer over-read or integer underflow condition that can be leveraged for remote code execution in some contexts, though the current exploitation primarily results in crash conditions.
Mitigation strategies for CVE-2015-8717 involve immediate patching of affected Wireshark installations to version 1.12.9 or later, which includes proper input validation for media count fields. Network administrators should also implement network segmentation and access controls to limit exposure to potentially malicious traffic. Additionally, organizations should consider implementing network-based intrusion detection systems that can identify and block malformed SDP packets before they reach vulnerable systems. This vulnerability aligns with CWE-129, which describes improper validation of array index values, and can be mapped to ATT&CK technique T1499.004 for denial of service attacks. The fix implemented in the patched versions includes validation checks that ensure media count values are non-negative integers before processing, preventing the application from attempting to use invalid values in memory operations. Organizations should also conduct regular vulnerability assessments to identify other potential protocol dissector flaws that could similarly affect network analysis tools.