CVE-2007-3072 in Firefox
Summary
by MITRE
Directory traversal vulnerability in Mozilla Firefox before 2.0.0.4 on Windows allows remote attackers to read arbitrary files via ..%5C (dot dot encoded backslash) sequences in a resource:// URI.
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Analysis
by VulDB Data Team • 07/31/2019
The vulnerability identified as CVE-2007-3072 represents a critical directory traversal flaw in Mozilla Firefox versions prior to 2.0.0.4 on Windows operating systems. This weakness stems from inadequate input validation within the browser's handling of resource URIs, specifically when processing encoded backslash sequences that should have been properly sanitized. The flaw enables remote attackers to bypass normal file access controls and retrieve arbitrary files from the victim's local filesystem through carefully crafted malicious URLs containing ..%5C sequences.
The technical implementation of this vulnerability exploits the way Firefox processes resource:// URIs on Windows platforms where the backslash character serves as a path separator. When the browser encounters encoded sequences such as ..%5C, it fails to properly normalize or validate these paths, allowing attackers to navigate up directory structures and access files that should remain protected. This behavior violates fundamental security principles of path validation and access control enforcement. The vulnerability specifically affects Windows systems due to the different path handling mechanisms between Windows and Unix-like systems, where backslashes are treated as directory separators while forward slashes are not.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with the capability to access sensitive files that may contain personal data, configuration settings, or even authentication credentials stored locally on the victim's system. Attackers can leverage this vulnerability to construct malicious web pages that automatically attempt to read system files, browser cache contents, or user-specific data without user interaction. This makes the vulnerability particularly dangerous in phishing attacks or when users visit compromised websites, as it can operate entirely in the background without user awareness. The vulnerability's exploitation requires no special privileges on the victim's machine and can be executed through standard web browsing activities.
Security mitigations for this vulnerability involve immediate patching of Firefox installations to version 2.0.0.4 or later, which includes proper input validation and path normalization routines. Organizations should also implement network-level protections such as web application firewalls that can detect and block suspicious URI patterns containing directory traversal sequences. Additionally, browser hardening measures including disabling unnecessary protocols and restricting file system access through browser configuration policies can provide additional defense layers. From a compliance perspective, this vulnerability aligns with CWE-22 Directory Traversal and maps to ATT&CK technique T1059.007 for command and scripting interpreter, as it enables attackers to execute reconnaissance activities through file system access. The vulnerability demonstrates the importance of proper input validation and the principle of least privilege in web browser security architecture, as it represents a failure to properly sanitize user-provided URI components before processing them within the application's security context.