CVE-2010-4567 in Bugzilla
Summary
by MITRE
Bugzilla before 3.2.10, 3.4.x before 3.4.10, 3.6.x before 3.6.4, and 4.0.x before 4.0rc2 does not properly handle whitespace preceding a (1) javascript: or (2) data: URI, which allows remote attackers to conduct cross-site scripting (XSS) attacks via the URL (aka bug_file_loc) field.
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Analysis
by VulDB Data Team • 10/13/2021
This vulnerability affects Bugzilla versions prior to specific patch releases, creating a cross-site scripting attack vector through improper handling of whitespace characters preceding javascript: or data: URIs. The flaw exists in the URL validation mechanism within the bug_file_loc field, which processes user-submitted URLs without adequate sanitization of leading whitespace characters. Attackers can exploit this by prepending whitespace to malicious URIs, bypassing input validation checks that would normally block such dangerous protocols. The vulnerability stems from a lack of proper URI parsing and validation, allowing attackers to inject malicious scripts that execute in the context of other users' browsers when they view affected bug reports.
The technical implementation of this vulnerability demonstrates a classic input sanitization failure where the application fails to normalize whitespace characters before validating URI schemes. This weakness enables attackers to craft malicious URLs that appear benign to basic validation but contain executable code when processed by web browsers. The issue affects multiple release branches including 3.2.10, 3.4.10, 3.6.4, and 4.0rc2, indicating a widespread problem in the Bugzilla codebase. The vulnerability specifically targets the URL field handling mechanism, where javascript: and data: URI schemes are particularly dangerous as they can execute arbitrary code within the victim's browser context, making this a high-severity XSS vulnerability.
The operational impact of this vulnerability extends beyond simple script execution, as it allows attackers to steal session cookies, perform actions on behalf of users, or redirect them to malicious sites. Users viewing affected bug reports would be exposed to these attacks without any indication that the content is compromised. The vulnerability is particularly concerning in bug tracking systems where users frequently click on URLs to access related resources, making the attack surface significant. This flaw can be leveraged for privilege escalation attacks if users have elevated permissions, as the malicious scripts could potentially access restricted functionalities or data within the Bugzilla application.
Mitigation strategies should focus on implementing proper input validation and sanitization of URL fields, including normalization of whitespace characters before URI scheme validation. Organizations should immediately upgrade to patched versions of Bugzilla, specifically versions 3.2.10, 3.4.10, 3.6.4, and 4.0rc2 or later. The fix typically involves modifying the URL handling logic to strip or normalize whitespace characters before performing protocol checks. Additionally, implementing Content Security Policy headers and input sanitization libraries can provide defense-in-depth measures. This vulnerability aligns with CWE-79 (Cross-site Scripting) and can be categorized under ATT&CK technique T1566 (Phishing) when used for social engineering attacks. The remediation approach should include comprehensive testing of URL handling functionality to ensure all whitespace variations are properly normalized before URI validation occurs.