CVE-2015-8731 in Wireshark
Summary
by MITRE
The dissct_rsl_ipaccess_msg function in epan/dissectors/packet-rsl.c in the RSL dissector in Wireshark 1.12.x before 1.12.9 and 2.0.x before 2.0.1 does not reject unknown TLV types, which allows remote attackers to cause a denial of service (out-of-bounds read and application crash) via a crafted packet.
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Analysis
by VulDB Data Team • 12/22/2024
The vulnerability identified as CVE-2015-8731 affects the RSL dissector component within Wireshark, specifically targeting the dissct_rsl_ipaccess_msg function located in epan/dissectors/packet-rsl.c. This flaw exists in Wireshark versions 1.12.x prior to 1.12.9 and 2.0.x prior to 2.0.1, representing a critical security issue that impacts the network protocol analysis tool's ability to process certain types of packets safely. The vulnerability stems from insufficient input validation within the dissector logic, which fails to properly handle unknown or unexpected TLV (Type-Length-Value) structures that may be present in RSL protocol messages used in GSM network communications.
The technical flaw manifests when the dissector encounters TLV elements that are not recognized or supported by the current version of the software. Instead of gracefully rejecting or properly handling these unknown TLV types, the function continues processing without adequate bounds checking, leading to out-of-bounds memory read operations. This improper handling occurs because the dissector does not validate whether the TLV type falls within expected ranges or supported values, allowing maliciously crafted packets to trigger memory access violations. The absence of proper input sanitization creates a condition where arbitrary data can be interpreted as valid protocol elements, causing unpredictable behavior in the application's memory management.
The operational impact of this vulnerability is significant as it enables remote attackers to execute a denial of service attack against systems running vulnerable versions of Wireshark. When a crafted packet containing unknown TLV types is processed by the affected dissector, the application experiences out-of-bounds read conditions that inevitably lead to application crashes. This creates a scenario where an attacker can remotely disrupt network analysis operations by simply transmitting specially constructed packets to a system running Wireshark in packet capture mode. The vulnerability is particularly concerning because it can be exploited without requiring authentication or specialized privileges, making it accessible to any remote attacker who can send packets to the target system.
The vulnerability aligns with CWE-129, which addresses improper validation of array indices, and specifically relates to improper input validation in protocol dissectors. From an ATT&CK framework perspective, this represents a denial of service technique that can be categorized under T1499.004, which covers network denial of service attacks. The flaw demonstrates poor defensive programming practices where input validation is insufficient to prevent exploitation of memory access violations. Organizations using Wireshark for network monitoring, forensic analysis, or security research are particularly at risk since these systems may encounter unexpected packet formats in real-world network traffic, especially when analyzing GSM network communications where RSL protocol messages are commonly found.
Mitigation strategies for CVE-2015-8731 include immediate patching of Wireshark installations to versions 1.12.9 or 2.0.1 and later, which contain the necessary fixes to properly validate TLV types before processing. Network administrators should also implement network segmentation and access controls to limit exposure of systems running Wireshark to potentially malicious traffic sources. Additionally, monitoring for unusual packet patterns and implementing intrusion detection systems can help identify exploitation attempts. Organizations should consider maintaining network traffic captures in a secure environment separate from the primary analysis systems, and regularly review and update their network protocol analysis tools to ensure they are running patched versions that address known vulnerabilities. The fix typically involves implementing proper bounds checking and input validation mechanisms that reject unknown TLV types rather than attempting to process them, thereby preventing the out-of-bounds memory access conditions that lead to application crashes.