CVE-2002-0402 in Ethereal
Summary
by MITRE
Buffer overflow in X11 dissector in Ethereal 0.9.3 and earlier allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code while Ethereal is parsing keysyms.
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Analysis
by VulDB Data Team • 09/28/2018
The vulnerability identified as CVE-2002-0402 represents a critical buffer overflow flaw within the X11 dissector component of Ethereal network protocol analyzer version 0.9.3 and earlier. This issue resides in the packet parsing functionality that processes X11 protocol data, specifically when handling keysym information during network traffic analysis. The buffer overflow occurs when Ethereal attempts to parse malformed X11 keysym data, causing the application to crash or potentially execute arbitrary code on the victim system. This vulnerability directly impacts the integrity and availability of network monitoring operations, as Ethereal serves as a fundamental tool for network administrators and security professionals to analyze traffic patterns and identify potential security threats.
The technical nature of this flaw stems from inadequate input validation within the X11 protocol dissector module. When Ethereal encounters X11 keysym data that exceeds the allocated buffer space, the application fails to properly handle the overflow condition, leading to memory corruption that can result in program termination or unauthorized code execution. This type of vulnerability falls under CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The flaw demonstrates poor defensive programming practices in handling untrusted network data, as the dissector does not implement proper bounds checking or input sanitization before processing X11 protocol elements.
Operationally, this vulnerability creates significant risks for network security operations and monitoring environments where Ethereal is deployed. An attacker could remotely exploit this flaw by crafting malicious X11 protocol packets containing oversized keysym data, causing Ethereal to crash and potentially gain remote code execution privileges. This would severely compromise network monitoring capabilities, as the tool responsible for detecting and analyzing network anomalies becomes unavailable or potentially compromised. The impact extends beyond simple denial of service, as successful exploitation could enable attackers to execute malicious code with the privileges of the Ethereal process, potentially leading to complete system compromise. Organizations relying on Ethereal for network traffic analysis face critical exposure, particularly in environments where network monitoring is essential for security operations.
The mitigation strategies for CVE-2002-0402 primarily involve immediate software updates to versions of Ethereal that address the buffer overflow vulnerability. Network administrators should upgrade to Ethereal 0.9.4 or later versions where the X11 dissector has been patched to properly validate input data and implement appropriate bounds checking. Additionally, implementing network segmentation and access controls can reduce the attack surface by limiting access to network monitoring tools. Organizations should also consider deploying intrusion detection systems that can identify and block malformed X11 protocol traffic patterns. From a defensive perspective, this vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation could enable attackers to execute arbitrary code on systems running vulnerable versions of Ethereal. The vulnerability also demonstrates the importance of maintaining current network security tool versions and implementing proper input validation as fundamental security practices to prevent similar issues in protocol analysis tools.