Mozilla Firefox has a vulnerability that allows the caching of the last filename used for printing a file. When generating a filename for printing, Firefox typically suggests the web page title. This caching mechanism, combined with the suggestion process, may result in the title of a website visited during private browsing mode being stored on disk. This vulnerability affects Firefox versions prior to 89.
The severity of this vulnerability is classified as medium, with a CVSS score of 4.3. The implications of this vulnerability could lead to unintended exposure of sensitive information, where users may inadvertently disclose titles of pages accessed during private browsing sessions.
Currently, there are no known exploits or public proofs of concept associated with CVE-2021-29960. However, the nature of the vulnerability warrants attention, especially considering the potential risks it poses to user privacy.
Organizations should prioritize patching this vulnerability immediately to mitigate risks associated with the exposure of sensitive titles during private browsing sessions.
Vulnerability Details
The official description of this vulnerability states that it allows the caching of web page titles in Firefox, which can lead to privacy issues. The vulnerability is classified under CWE-669. The attack vector is classified as network-based with low complexity and requires user interaction. The confidentiality impact is low, while the integrity and availability impacts are none.
Firefox versions affected include all versions prior to 89. The vulnerability was published on June 24, 2021.
Technical Analysis
The root cause of this vulnerability is the improper handling of cached filenames in the printing functionality of Firefox. When a user prints a document from a web page, Firefox suggests a filename based on the title of the page, which is stored in cache. If a user accesses sensitive pages in private browsing mode, the titles of these pages can be cached and potentially exposed.
The attack complexity is low, as exploitation does not require advanced skills. User interaction is necessary, as the user must initiate the printing process. The confidentiality impact is low, as only the titles of pages are cached, with no impact on integrity or availability.
Risk & Impact Analysis
Risk to organizations includes the potential exposure of sensitive information, which could lead to privacy violations. The blast radius of this vulnerability is limited to users who utilize the printing feature in Firefox while in private browsing mode. Given the current lack of known exploits, the urgency is moderate, and organizations should address this in their priority patch cycle.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
All versions of Mozilla Firefox prior to version 89 are affected by this vulnerability. Organizations should verify their installed versions and apply the necessary patches.
Mitigation & Remediation
Organizations should update to the latest version of Mozilla Firefox to mitigate this vulnerability. The patched version is 89.0 or newer. If immediate patching is not possible, consider implementing workarounds such as limiting the use of printing from private browsing mode.
Detection Guidance
Monitoring for abnormal caching behavior in Firefox and reviewing logs for any unusual printing requests from private browsing sessions may help in detecting potential exploitation attempts.
AppSecure Threat Intelligence Insight
The long-term significance of this vulnerability lies in its representation of how caching mechanisms can inadvertently expose user data. Security teams should take this as a lesson to ensure that sensitive information is not cached during any browsing mode, especially in private sessions.
Organizations should implement stringent control measures to manage how their web applications handle sensitive data and utilize security assessments to identify similar weaknesses.
Security teams can refer to best practices for effective application security assessments and consider engaging in application security assessments to enhance their security posture.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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