CVE-2020-15098 : Security Advisory and Response

In TYPO3 CMS versions greater than or equal to 9.0.0 and less than 9.5.20, as well as versions greater than or equal to 10.0.0 and less than 10.4.6, a vulnerability has been identified that allows the generation of arbitrary checksums through an internal verification mechanism. This flaw enables the injection of arbitrary data with a valid cryptographic message authentication code (HMAC-SHA1), potentially leading to privilege escalation, insecure deserialization, and remote code execution. The severity of this vulnerability is high due to the possible attack chains and the requirement of a valid backend user session.

Understanding CVE-2020-15098

This CVE pertains to a security issue in TYPO3 CMS that could result in sensitive information disclosure and various attack vectors.

What is CVE-2020-15098?

This CVE describes a vulnerability in TYPO3 CMS versions that allows the generation of arbitrary checksums, leading to potential privilege escalation, insecure deserialization, and remote code execution.

The Impact of CVE-2020-15098

The vulnerability poses a high risk due to the potential attack chains it enables, including privilege escalation, insecure deserialization, and remote code execution.

Technical Details of CVE-2020-15098

The technical aspects of the vulnerability in TYPO3 CMS.

Vulnerability Description

The flaw allows the generation of arbitrary checksums through an internal verification mechanism, enabling the injection of arbitrary data with a valid cryptographic message authentication code (HMAC-SHA1).

Affected Systems and Versions

TYPO3 CMS versions >= 9.0.0, < 9.5.20
TYPO3 CMS versions >= 10.0.0, < 10.4.6

Exploitation Mechanism

The vulnerability can be exploited by injecting arbitrary data with a valid cryptographic message authentication code, potentially leading to privilege escalation, insecure deserialization, and remote code execution.

Mitigation and Prevention

Steps to mitigate and prevent the exploitation of CVE-2020-15098.

Immediate Steps to Take

Update TYPO3 CMS to versions 9.5.20 and 10.4.6, where the vulnerability has been patched.
Monitor backend user sessions for any unauthorized activities.

Long-Term Security Practices

Regularly update and patch TYPO3 CMS to the latest versions to prevent security vulnerabilities.
Implement strong access controls and authentication mechanisms to secure backend user sessions.

Patching and Updates

Ensure timely installation of security patches and updates provided by TYPO3 to address known vulnerabilities.