CVE-2007-0780 in Firefox
Summary
by MITRE
browser.js in Mozilla Firefox 1.5.x before 1.5.0.10 and 2.x before 2.0.0.2, and SeaMonkey before 1.0.8 uses the requesting URI to identify child windows, which allows remote attackers to conduct cross-site scripting (XSS) attacks by opening a blocked popup originating from a javascript: URI in combination with multiple frames having the same data: URI.
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Analysis
by VulDB Data Team • 07/13/2021
The vulnerability described in CVE-2007-0780 represents a critical cross-site scripting flaw in Mozilla Firefox and SeaMonkey browsers that stems from improper handling of window identification mechanisms. This issue affects versions of Firefox 1.5.x prior to 1.5.0.10 and 2.x prior to 2.0.0.2, as well as SeaMonkey versions before 1.0.8, making it a widespread concern across multiple browser iterations. The flaw specifically resides in the browser.js script which manages how child windows are identified and tracked within the browser environment.
The technical implementation of this vulnerability exploits a fundamental weakness in the browser's popup management system where the requesting URI is used as the primary identifier for child windows. When a malicious actor crafts a javascript: URI that opens a blocked popup, the browser's window identification mechanism fails to properly distinguish between legitimate and malicious contexts. This misidentification becomes particularly dangerous when combined with multiple frames that share the same data: URI, creating a scenario where an attacker can manipulate the browser's window tracking behavior to execute malicious code in the context of a different origin than intended.
The operational impact of this vulnerability extends beyond simple XSS exploitation as it enables attackers to bypass security boundaries that should normally prevent cross-origin script execution. The attack vector specifically leverages the interaction between javascript: URIs and data: URIs within a multi-frame environment, allowing an attacker to inject malicious scripts that can execute with the privileges and context of the target domain. This creates a significant risk for users who may inadvertently visit compromised websites that utilize this technique to compromise their browsing sessions.
From a cybersecurity perspective, this vulnerability aligns with CWE-79 which describes cross-site scripting flaws, and demonstrates characteristics consistent with ATT&CK technique T1059.007 for script-based attacks. The flaw represents a classic case of insufficient input validation and improper context management in browser security mechanisms. Security researchers have noted that this vulnerability particularly affects web applications that rely on popup blocking features and frame-based navigation patterns, making it a significant concern for enterprise environments where such patterns are common. The vulnerability's exploitation requires specific conditions involving multiple frames and URI types, but the potential impact on user sessions and data confidentiality makes it a serious concern that warranted immediate patching.
Organizations should prioritize updating affected browser versions to the patched releases mentioned in the CVE description, as well as implementing additional security measures such as content security policies and enhanced popup blocking configurations. The vulnerability highlights the importance of proper window identification and context management in browser security architecture, emphasizing that even seemingly minor implementation details in core browser components can lead to significant security weaknesses. Network administrators should monitor for exploitation attempts targeting this specific vulnerability and ensure that all browser installations remain current with security patches.