CVE-2021-21123 is a medium-severity vulnerability affecting Google Chrome and Microsoft Edge Chromium. This vulnerability allows insufficient data validation in the File System API, which can be exploited by a remote attacker via a crafted HTML page. The CVSS score for this vulnerability is 6.5, indicating a medium risk level. Organizations using affected browsers must take this issue seriously to prevent unauthorized access to sensitive filesystem data.
The risk to organizations includes the potential for attackers to manipulate filesystem restrictions, leading to unauthorized data access and integrity issues. User interaction is required for exploitation, as victims must visit a malicious webpage for the attack to be successful. Given the relatively low complexity of the attack and the potential impact, organizations should prioritize a timely response.
Currently, there is no known public exploit available, but a proof-of-concept has been found on GitHub, which indicates that exploitation is a possibility. Organizations must remain vigilant and consider patching strategies in their security practices to mitigate this vulnerability effectively.
Organizations should prioritize patching immediately. Google has addressed this vulnerability in their updates, and users should ensure that they are running the latest version of Chrome (88.0.4324.96 or later) or Edge Chromium (88.0.705.50 or later) to protect against potential exploits.
Vulnerability Details
Insufficient data validation in the File System API in Google Chrome prior to 88.0.4324.96 allowed a remote attacker to bypass filesystem restrictions via a crafted HTML page. The CVSS score is 6.5, classifying this as a medium severity issue, primarily affecting the confidentiality and integrity of user data.
The vulnerability is classified under CWE-20, which pertains to improper input validation. This indicates a failure in the system's ability to adequately verify user input before processing it, potentially allowing for exploitation.
Affected products include any versions of Google Chrome prior to 88.0.4324.96 and Microsoft Edge Chromium prior to 88.0.705.50. The vulnerability was published on February 9, 2021, and it has been categorized as modified since then.
Technical Analysis
The root cause of CVE-2021-21123 stems from insufficient data validation within the File System API. The attack vector is network-based, meaning that a successful exploit can occur remotely without physical access to the user’s device. The attack complexity is low, and no privileges are required for the attacker, making this vulnerability particularly concerning.
User interaction is required, as the victim must navigate to a malicious webpage that facilitates the attack. The confidentiality impact is noted as none, while the integrity impact is high, indicating that attackers could potentially alter data without detection. Availability impact is noted as none, which means the exploit does not disrupt service availability.
Risk & Impact Analysis
The real-world deployment risk of CVE-2021-21123 is significant, considering the widespread use of both Google Chrome and Microsoft Edge Chromium. With millions of users potentially vulnerable, the blast radius of this vulnerability could be large, allowing attackers to exploit unpatched systems on a wide scale.
Risk to organizations includes the potential for unauthorized data manipulation and integrity breaches, which could have serious consequences for data security and user trust. Given the CVSS score of 6.5, organizations should address this vulnerability in their priority patch cycle.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | Yes |
Public PoC | Yes |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
Affected versions include Google Chrome prior to 88.0.4324.96 and Microsoft Edge Chromium prior to 88.0.705.50. Organizations should ensure all systems are updated to these versions or later to mitigate this vulnerability.
Mitigation & Remediation
To remediate CVE-2021-21123, organizations must apply the latest updates for Google Chrome and Microsoft Edge. Users should upgrade to Chrome version 88.0.4324.96 or later and Edge version 88.0.705.50 or later. In cases where immediate patching is not possible, consider implementing strict content security policies and monitoring to detect potential exploitation attempts.
For enhanced security posture, organizations can engage in penetration testing to assess the effectiveness of patches and identify similar vulnerabilities.
Detection Guidance
Organizations should monitor logs for anomalies related to filesystem access requests and unusual HTML page interactions. Look for behavioral indicators that suggest exploitation attempts, such as unexpected user requests or access patterns. Implement network signatures that track suspicious activities linked to this vulnerability.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2021-21123 highlights the ongoing challenges organizations face in securing web applications against evolving threats. This vulnerability exemplifies the need for continuous security assessments and proactive measures to guard against similar issues.
Security teams should focus on implementing robust input validation mechanisms and regular code reviews to prevent similar vulnerabilities in the future. The lessons from this incident reinforce the importance of adopting a comprehensive security strategy that includes both proactive and reactive measures.
For more insights on securing web applications, explore our resources on web application penetration testing and best practices for mitigating vulnerabilities.
Additionally, engaging in penetration testing methodology allows organizations to identify and address weaknesses effectively.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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