CVE-2021-27329 : Exploit Details and Defense Strategies

Friendica 2021.01 allows SSRF via parse_url?binurl= for DNS lookups or HTTP requests to arbitrary domain names.

Understanding CVE-2021-27329

This CVE identifies a Server-Side Request Forgery (SSRF) vulnerability in Friendica 2021.01, which can be exploited through the parse_url?binurl= endpoint.

What is CVE-2021-27329?

CVE-2021-27329 points to an SSRF issue in Friendica 2021.01, enabling attackers to manipulate DNS lookups and send HTTP requests to any domain.

The Impact of CVE-2021-27329

This vulnerability could lead to unauthorized access to internal systems, data exposure, or even complete server compromise if exploited by malicious actors.

Technical Details of CVE-2021-27329

Below are the technical aspects of CVE-2021-27329:

Vulnerability Description

Friendica 2021.01 is susceptible to SSRF attacks, allowing threat actors to conduct arbitrary DNS queries and HTTP requests using the parse_url?binurl= feature.

Affected Systems and Versions

All instances of Friendica 2021.01 are affected by this vulnerability.

Exploitation Mechanism

By exploiting the SSRF vulnerability in the parse_url?binurl= endpoint, attackers can trick the server into making requests on their behalf to external domains.

Mitigation and Prevention

To safeguard systems from CVE-2021-27329, the following measures should be taken:

Immediate Steps to Take

Disable the parse_url?binurl= feature in Friendica 2021.01 to prevent SSRF attacks.
Implement strict input validation for URLs to mitigate the risk of SSRF vulnerabilities.

Long-Term Security Practices

Regularly update Friendica to the latest version to patch known vulnerabilities.
Conduct security audits to identify and address any potential SSRF issues in the application.

Patching and Updates

Apply security patches released by Friendica promptly to address CVE-2021-27329 and other security flaws.