CVE-2006-2785 in Firefox
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Mozilla Firefox before 1.5.0.4 allows user-assisted remote attackers to inject arbitrary web script or HTML by tricking a user into (1) performing a "View Image" on a broken image in which the SRC attribute contains a Javascript URL, or (2) selecting "Show only this frame" on a frame whose SRC attribute contains a Javascript URL.
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Analysis
by VulDB Data Team • 06/20/2019
This cross-site scripting vulnerability exists in mozilla firefox versions prior to 1.5.0.4 and represents a classic user-assisted attack vector that exploits the browser's handling of javascript urls within image and frame source attributes. The flaw allows remote attackers to execute arbitrary web scripts or html code through social engineering techniques that trick users into performing specific actions within the browser interface. The vulnerability specifically targets the browser's image viewing functionality and frame handling mechanisms, creating a dangerous intersection between user interaction and code execution.
The technical implementation of this vulnerability relies on the browser's failure to properly sanitize javascript urls contained within the src attributes of html elements. When a user performs a "view image" action on an image with a javascript url in its src attribute, or selects "show only this frame" on a frame containing a javascript url, the browser executes the malicious javascript code without adequate input validation or sanitization. This behavior violates fundamental security principles of input validation and output encoding that should prevent such code execution contexts from being created. The vulnerability is classified as a type of reflected cross-site scripting according to the cwe taxonomy under cwe-79 which specifically addresses improper neutralization of input during web page generation.
The operational impact of this vulnerability is significant as it enables attackers to perform a wide range of malicious activities including session hijacking, credential theft, redirection to malicious sites, and data exfiltration. Attackers can craft malicious web pages that, when viewed by victims using vulnerable firefox versions, automatically execute javascript payloads that can steal cookies, capture keystrokes, or modify the browser's content. The user-assisted nature of the attack means that social engineering plays a crucial role in successful exploitation, as victims must be tricked into performing specific actions that trigger the vulnerable code paths. This makes the vulnerability particularly dangerous in phishing campaigns or when users visit compromised websites that contain crafted malicious content.
The attack vectors described in the vulnerability specifically target the browser's user interface elements where image viewing and frame manipulation occur. The first vector involves broken image handling where the browser's image viewer processes javascript urls in the src attribute without proper sanitization. The second vector involves frame manipulation where the browser's frame handling logic fails to prevent javascript execution when users select the "show only this frame" option. Both attack scenarios demonstrate the browser's insufficient security controls around dynamic content loading and execution contexts. This vulnerability aligns with several att&ck techniques including t1059 command and scripting interpreter and t1566 credential access through social engineering.
Mitigation strategies for this vulnerability include immediate upgrading to firefox version 1.5.0.4 or later where the issue has been patched. The patch addresses the root cause by implementing proper input sanitization and validation for javascript urls in image and frame source attributes. Additionally, users should exercise caution when viewing images or frames from untrusted sources and should be aware of social engineering tactics that may lead to exploitation. Organizations should implement web application firewalls and content filtering systems to detect and block javascript urls in image and frame attributes. Browser security enhancements including strict content security policies and sandboxing mechanisms can also provide additional protection layers against similar vulnerabilities. The incident highlights the importance of comprehensive input validation and the need for web browsers to maintain robust security controls around dynamic content handling operations.