CVE-2010-2769 in Firefox
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Mozilla Firefox before 3.5.12 and 3.6.x before 3.6.9, Thunderbird before 3.0.7 and 3.1.x before 3.1.3, and SeaMonkey before 2.0.7 allows user-assisted remote attackers to inject arbitrary web script or HTML via a selection that is added to a document in which the designMode property is enabled.
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Analysis
by VulDB Data Team • 09/24/2021
This cross-site scripting vulnerability exists in multiple Mozilla applications including Firefox, Thunderbird, and SeaMonkey, affecting versions prior to specific security patches. The flaw occurs when a malicious actor crafts a crafted selection that gets inserted into a document where the designMode property is enabled, creating a vector for arbitrary script execution. The vulnerability represents a classic client-side attack scenario where user interaction is required to trigger the malicious payload. According to CWE-79, this maps directly to Cross-Site Scripting vulnerabilities that allow attackers to inject malicious scripts into web pages viewed by other users. The designMode property in web browsers enables editing capabilities on contentEditable elements, but when combined with improper input sanitization, it creates a dangerous attack surface.
The technical implementation of this vulnerability exploits the interaction between browser document editing capabilities and script injection mechanisms. When a document has designMode enabled, it allows for rich text editing operations that can be manipulated through JavaScript. Attackers can leverage this by creating malicious selections that contain embedded scripts, which then execute when the selection is processed within the document context. The vulnerability requires user interaction as the attacker must convince a victim to perform an action that triggers the injection mechanism, typically through phishing emails or malicious web content. This user-assisted nature reduces the attack surface but does not eliminate the risk, as social engineering remains a significant threat vector in web security. The ATT&CK framework categorizes this under T1203 - Exploitation for Client Execution, where attackers leverage browser vulnerabilities to execute malicious code in the context of the user's session.
The operational impact of this vulnerability extends beyond simple script injection, as it can enable more sophisticated attacks including session hijacking, credential theft, and data exfiltration. Attackers can exploit the vulnerability to create persistent malicious content that executes in the victim's browser context, potentially compromising sensitive information. The affected applications represent critical communication tools where the vulnerability could be exploited to compromise email communications or web browsing sessions. Organizations using these vulnerable versions face significant risk, particularly in environments where users interact with untrusted web content or receive email from external sources. The vulnerability affects not just individual users but also enterprise environments where these applications are widely deployed. Security teams must prioritize patching these vulnerabilities as they represent a direct threat to user security and data integrity.
Mitigation strategies should focus on immediate patch deployment across all affected versions of the vulnerable applications. Organizations should implement comprehensive application update policies to ensure all systems receive security patches promptly. Browser security configurations should include restrictions on designMode usage where possible, and input validation should be strengthened to prevent malicious content insertion. Network-based protections such as web application firewalls can provide additional layers of defense, though they cannot fully compensate for the underlying vulnerability. User education programs should emphasize the importance of avoiding suspicious links and content, as the vulnerability requires user interaction to be exploited. Regular security assessments should verify that all systems are running patched versions, and monitoring should be implemented to detect potential exploitation attempts. The vulnerability also underscores the importance of keeping all browser applications updated, as the interconnected nature of web technologies means that security issues in one component can affect broader application ecosystems.