CVE-1999-1227 in Ethereal
Summary
by MITRE
Ethereal allows local users to overwrite arbitrary files via a symlink attack on the packet capture file.
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Analysis
by VulDB Data Team • 04/19/2026
The vulnerability described in CVE-1999-1227 represents a critical security flaw in Ethereal, a network protocol analyzer that was widely used for capturing and analyzing network traffic. This vulnerability specifically affects the application's handling of packet capture files and creates a significant attack vector for local users who can manipulate the system through symbolic link attacks. The flaw stems from the application's insufficient validation of file paths and its failure to properly handle symbolic links during file operations, which allows malicious users to redirect file creation to arbitrary locations on the filesystem.
The technical implementation of this vulnerability involves a classic symlink attack pattern where an attacker creates symbolic links with specific names that match the expected packet capture filenames. When Ethereal attempts to write its capture data to these locations, it follows the symbolic links and writes data to the target files specified in the link rather than the intended location. This type of vulnerability falls under CWE-59, which describes improper handling of symbolic links, and represents a privilege escalation issue that can be exploited by local users to overwrite critical system files or inject malicious content into unexpected locations. The flaw particularly affects systems where Ethereal runs with elevated privileges or where users have the ability to create files in directories where the application expects to write capture files.
The operational impact of this vulnerability extends beyond simple file overwriting, as it can potentially allow attackers to compromise system integrity and availability. Local users who can execute commands on the system can leverage this flaw to overwrite configuration files, system binaries, or other critical resources that might be targeted through carefully crafted symbolic links. The attack requires the user to have local access to the system and knowledge of the application's file handling behavior, but once exploited, it can provide persistent access or cause system instability. This vulnerability is particularly concerning in environments where Ethereal is run with elevated privileges or where multiple users share the same system, as it could enable privilege escalation attacks that bypass normal access controls. The attack vector aligns with ATT&CK technique T1059, which covers command and scripting interpreter usage, and T1548, which addresses abuse of privilege escalation techniques through local system modifications.
Mitigation strategies for CVE-1999-1227 require immediate implementation of proper file path validation and secure file handling practices within the application. System administrators should ensure that Ethereal is not run with unnecessary elevated privileges and that proper file permissions are enforced on directories where packet capture files are stored. The recommended approach involves implementing proper symlink detection and validation mechanisms that check for symbolic links before file operations, as well as using secure temporary file creation methods that prevent attackers from creating malicious links in the target directories. Additionally, regular security audits should verify that applications properly handle file operations and that no insecure file handling patterns exist within the codebase. Organizations should also consider implementing monitoring solutions to detect suspicious file creation patterns and unauthorized symbolic link modifications that might indicate exploitation attempts. The vulnerability demonstrates the importance of secure coding practices and proper input validation, particularly when dealing with file system operations that could be influenced by external factors or user-controlled data.