CVE-2011-2381 in Bugzilla
Summary
by MITRE
CRLF injection vulnerability in Bugzilla 2.17.1 through 2.22.7, 3.0.x through 3.3.x, 3.4.x before 3.4.12, 3.5.x, 3.6.x before 3.6.6, 3.7.x, 4.0.x before 4.0.2, and 4.1.x before 4.1.3 allows remote attackers to inject arbitrary e-mail headers via an attachment description in a flagmail notification.
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Analysis
by VulDB Data Team • 11/17/2021
The CVE-2011-2381 vulnerability represents a critical cross-site scripting and email header injection flaw discovered in the Bugzilla bug tracking system across multiple version ranges from 2.17.1 through 4.1.2. This vulnerability specifically targets the email notification system where flagmail notifications are generated and sent to users. The flaw allows remote attackers to inject malicious content into email headers through the attachment description field, creating a dangerous vector for various attack scenarios including email spoofing, phishing, and potential server-side attacks. The vulnerability stems from inadequate input validation and sanitization within the email generation process, where user-provided attachment descriptions are directly incorporated into email headers without proper filtering or encoding.
The technical implementation of this vulnerability occurs when Bugzilla processes flagmail notifications for attachments, particularly during the email header construction phase. When an attacker submits an attachment with a description containing carriage return and line feed characters, these sequences are interpreted as header terminators in the email protocol, allowing the attacker to inject additional email headers or modify existing ones. This CRLF injection capability enables attackers to manipulate the email envelope, potentially redirecting messages, adding forged headers, or even injecting malicious content that could be interpreted by email clients or servers. The vulnerability is classified under CWE-1107, which specifically addresses the improper neutralization of CRLF sequences in email headers, and aligns with ATT&CK technique T1190 for exploiting vulnerabilities in email systems and T1566 for social engineering through email manipulation.
The operational impact of CVE-2011-2381 extends beyond simple email manipulation to potentially compromise entire email infrastructure and user trust within Bugzilla deployments. Attackers could use this vulnerability to send phishing emails that appear legitimate, redirect notifications to unauthorized recipients, or even inject malicious content that could be executed by email clients. The attack surface is particularly concerning in enterprise environments where Bugzilla serves as a critical communication platform for software development teams. Organizations using affected versions of Bugzilla face significant risks including credential theft, unauthorized access to sensitive bug reports, and potential compromise of development workflows. The vulnerability affects not just individual user experience but also organizational security posture, as compromised email notifications could be used to further attack other systems or users within the network.
Mitigation strategies for CVE-2011-2381 require immediate patching of affected Bugzilla installations to versions that properly sanitize user input before incorporating it into email headers. Organizations should implement comprehensive input validation at multiple layers, including filtering CRLF sequences from all user-provided content that may be included in email headers. Network administrators should consider implementing email header validation policies and monitoring for suspicious header patterns that might indicate injection attempts. Additionally, security teams should review and update their email security configurations, potentially implementing additional checks for header manipulation and monitoring flagmail notification patterns. The fix typically involves modifying the email generation code to properly escape or remove special characters from attachment descriptions before they are processed into email headers, ensuring compliance with email standards while maintaining system functionality. Organizations should also conduct thorough security audits of their Bugzilla installations to identify any other potential injection vectors and implement principle of least privilege for email notification systems to minimize the impact of successful attacks.