CVE-2017-9349 in Wireshark
Summary
by MITRE
In Wireshark 2.2.0 to 2.2.6 and 2.0.0 to 2.0.12, the DICOM dissector has an infinite loop. This was addressed in epan/dissectors/packet-dcm.c by validating a length value.
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Analysis
by VulDB Data Team • 12/07/2022
The vulnerability identified as CVE-2017-9349 represents a critical denial of service flaw within Wireshark's DICOM protocol dissector. This issue affects versions 2.2.0 through 2.2.6 and 2.0.0 through 2.0.12, creating a scenario where the network protocol analyzer becomes unresponsive due to an infinite loop condition. The DICOM dissector is responsible for parsing Digital Imaging and Communications in Medicine protocol data, which is commonly used in healthcare environments for storing and transmitting medical images and related information. When processing malformed DICOM packets, the dissector enters an infinite loop that consumes excessive CPU resources and prevents normal packet analysis operations from continuing.
The technical root cause of this vulnerability stems from insufficient input validation within the packet-dcm.c file in Wireshark's epan/dissectors directory. Specifically, the dissector fails to properly validate length values contained within DICOM packet structures before using them in loop conditions. This validation gap allows attackers to craft specially malformed DICOM packets that contain incorrect or malicious length fields, which when processed by the dissector trigger an infinite loop. The flaw is categorized under CWE-835 as an infinite loop without a countermeasure, where the loop condition never reaches a termination state due to improper input validation. The vulnerability demonstrates poor defensive programming practices and highlights the importance of implementing proper bounds checking and input sanitization in protocol parsing components.
The operational impact of CVE-2017-9349 extends beyond simple service disruption to potentially compromise entire network monitoring operations. When an infinite loop occurs in Wireshark's dissector, it causes the application to become unresponsive and consume 100% CPU resources, effectively making it unusable for network analysis. This situation is particularly concerning in healthcare environments where Wireshark is commonly used for troubleshooting medical device communications, as it can prevent critical network diagnostics from being performed. Network administrators and security professionals who rely on Wireshark for monitoring and analyzing DICOM traffic across hospital networks may find their monitoring capabilities completely compromised, potentially masking other security issues or network problems that require analysis. The vulnerability also affects automated network monitoring systems that depend on Wireshark for continuous packet analysis, leading to potential blind spots in network security monitoring.
Mitigation strategies for CVE-2017-9349 focus primarily on upgrading to patched versions of Wireshark where the issue has been resolved through proper input validation. The fix implemented in packet-dcm.c involves adding validation checks to ensure that length values are properly bounded before being used in loop constructs, preventing the infinite loop condition from occurring. Organizations should also implement network segmentation and access controls to limit exposure to potentially malicious DICOM traffic, particularly in healthcare environments where such protocols are prevalent. Network monitoring solutions should include automated detection of high CPU utilization patterns that may indicate the presence of this vulnerability, enabling rapid response to potential exploitation attempts. From an ATT&CK framework perspective, this vulnerability aligns with T1499.004 (Resource Hijacking) and T1566.001 (Phishing with Malicious Attachments), as it can be exploited through malicious packet crafting to consume system resources and potentially disrupt critical network operations. Regular security assessments and network traffic monitoring should include checks for vulnerable Wireshark versions to prevent exploitation of this and similar protocol parsing vulnerabilities.