CVE-2002-0353 in Ethereal
Summary
by MITRE
The ASN.1 parser in Ethereal 0.9.2 and earlier allows remote attackers to cause a denial of service (crash) via a certain malformed packet, which causes Ethereal to allocate memory incorrectly, possibly due to zero-length fields.
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Analysis
by VulDB Data Team • 06/18/2024
The vulnerability identified as CVE-2002-0353 resides within the ASN.1 parser implementation of Ethereal network protocol analyzer version 0.9.2 and earlier. This flaw represents a critical memory management issue that can be exploited remotely to trigger a denial of service condition. The vulnerability specifically targets the parser's handling of malformed ASN.1 encoded packets, which are commonly used in various network protocols including LDAP, X.509 certificates, and SNMP. When Ethereal encounters such malformed packets during network traffic analysis, the parser fails to properly validate the structure and length of ASN.1 elements, leading to improper memory allocation behavior.
The technical root cause of this vulnerability stems from inadequate input validation within the ASN.1 parsing logic. When processing packets containing zero-length fields or other malformed ASN.1 structures, the parser attempts to allocate memory based on incorrect or malformed length indicators. This improper memory handling creates a condition where the application may attempt to allocate zero bytes or extremely large memory blocks, ultimately resulting in a crash of the Ethereal process. The vulnerability is classified under CWE-129 as an Improper Validation of Array Index, and more specifically relates to CWE-704 as an Incorrect Type Conversion or Cast, since the parser fails to properly validate the data types and lengths during ASN.1 structure parsing. This flaw falls within the ATT&CK technique T1499.004 for Network Denial of Service, as it specifically targets network protocol analysis tools to prevent their operation.
The operational impact of this vulnerability extends beyond simple service disruption, as it affects the reliability and availability of network monitoring and forensic analysis capabilities. Network administrators and security analysts who rely on Ethereal for network traffic inspection and protocol analysis would face complete loss of monitoring functionality when encountering maliciously crafted packets. The vulnerability is particularly dangerous in environments where network analysis tools are deployed for security monitoring, as attackers could exploit this weakness to disrupt critical network visibility infrastructure. Additionally, since Ethereal was widely used for security research and network troubleshooting, this vulnerability could potentially be leveraged to prevent security professionals from performing essential network analysis tasks, thereby weakening overall network security posture.
Mitigation strategies for CVE-2002-0353 primarily focus on immediate software updates and defensive measures. The most effective solution involves upgrading to Ethereal version 0.9.3 or later, which includes proper input validation and memory allocation handling for ASN.1 structures. Organizations should also implement network segmentation and access controls to limit exposure to potentially malicious traffic, while deploying intrusion detection systems that can identify and block malformed packets targeting this specific vulnerability. Network administrators should consider implementing protocol filtering rules that can identify and drop packets with suspicious ASN.1 structures before they reach the Ethereal analyzer. Additionally, regular security assessments and vulnerability scanning should be conducted to identify any other potentially vulnerable network analysis tools that might be susceptible to similar memory corruption issues. The vulnerability demonstrates the critical importance of proper input validation in protocol parsers, as highlighted by ATT&CK technique T1210 for Exploitation of Remote Services, where inadequate validation can lead to arbitrary code execution or service disruption.