CVE-2020-15810 : What You Need to Know

An issue was discovered in Squid before 4.13 and 5.x before 5.0.4, allowing HTTP Request Smuggling attacks that lead to cache poisoning.

Understanding CVE-2020-15810

This CVE involves incorrect data validation in Squid, potentially enabling HTTP Request Smuggling attacks.

What is CVE-2020-15810?

Incorrect data validation in Squid versions before 4.13 and 5.x before 5.0.4
Allows HTTP Request Smuggling attacks against HTTP and HTTPS traffic
Leads to cache poisoning, enabling clients to bypass security and poison proxy and downstream caches

The Impact of CVE-2020-15810

Successful exploitation can lead to cache poisoning and compromise the integrity of cached content
Attackers can manipulate headers to bypass security measures and inject malicious content

Technical Details of CVE-2020-15810

This section provides more technical insights into the vulnerability.

Vulnerability Description

Squid before 4.13 and 5.x before 5.0.4 are vulnerable
Relaxed header parsing allows whitespace characters to be relayed to upstream servers
Incorrect handling of Content-Length headers can lead to conflicting length usage

Affected Systems and Versions

Squid versions before 4.13 and 5.x before 5.0.4

Exploitation Mechanism

Attackers can exploit relaxed header parsing to manipulate Content-Length headers
By sending conflicting lengths, attackers can poison caches with arbitrary content

Mitigation and Prevention

Protecting systems from CVE-2020-15810 requires immediate actions and long-term security practices.

Immediate Steps to Take

Update Squid to version 4.13 or 5.0.4 to mitigate the vulnerability
Monitor and filter incoming requests to detect and block potential HTTP Request Smuggling attempts

Long-Term Security Practices

Regularly update and patch Squid and other software to address security vulnerabilities
Implement secure coding practices and conduct security assessments to identify and remediate potential issues

Patching and Updates

Apply patches provided by Squid to fix the incorrect data validation issue
Stay informed about security advisories and updates from Squid and relevant vendors