CVE-2021-27693 : Security Advisory and Response
Learn about CVE-2021-27693, a critical SSRF vulnerability in PublicCMS before 4.0.202011.b. Understand the impact, affected systems, exploitation mechanism, and mitigation steps.
A Server-side Request Forgery (SSRF) vulnerability in PublicCMS before version 4.0.202011.b allows attackers to exploit the system via an endpoint when the action is catchimage.
Understanding CVE-2021-27693
This CVE record highlights a critical security issue present in PublicCMS software.
What is CVE-2021-27693?
The CVE-2021-27693 vulnerability is classified as a Server-side Request Forgery (SSRF) flaw in PublicCMS before version 4.0.202011.b. It specifically occurs when the /publiccms/admin/ueditor endpoint is manipulated with the action parameter set to catchimage.
The Impact of CVE-2021-27693
This vulnerability can be exploited by threat actors to perform unauthorized requests from the server, potentially leading to data breaches, information leakage, or complete system compromise.
Technical Details of CVE-2021-27693
PublicCMS versions prior to 4.0.202011.b are affected by this SSRF vulnerability.
Vulnerability Description
The SSRF vulnerability arises in the /publiccms/admin/ueditor endpoint when the action parameter is set to catchimage, enabling attackers to manipulate server requests.
Affected Systems and Versions
All versions of PublicCMS before 4.0.202011.b are vulnerable to this exploit.
Exploitation Mechanism
Attackers can abuse the SSRF vulnerability in PublicCMS by sending crafted requests to the catchimage action, allowing them to interact with internal systems and potentially exfiltrate sensitive data.
Mitigation and Prevention
To safeguard systems from CVE-2021-27693, immediate actions and long-term security measures are essential.
Immediate Steps to Take
- Update PublicCMS to version 4.0.202011.b or later to mitigate the SSRF vulnerability.
- Implement network controls to restrict access to the /publiccms/admin/ueditor endpoint.
Long-Term Security Practices
- Regularly monitor and audit server logs for suspicious activities.
- Educate users and administrators about the risks of SSRF attacks and how to report potential security incidents.
Patching and Updates
Stay informed about security updates and patches released by PublicCMS to address vulnerabilities like CVE-2021-27693.