CVE-2020-5303 : Security Advisory and Response

Tendermint before versions 0.33.3, 0.32.10, and 0.31.12 has a denial-of-service vulnerability due to uncontrolled memory allocation. This can lead to Out-Of-Memory exceptions and potential system crashes.

Understanding CVE-2020-5303

This CVE identifies a denial-of-service vulnerability in Tendermint versions prior to 0.33.3, 0.32.10, and 0.31.12.

What is CVE-2020-5303?

CVE-2020-5303 is a vulnerability in Tendermint that allows attackers to exploit uncontrolled memory allocation, leading to memory spikes, Out-Of-Memory exceptions, and potential system crashes.

The Impact of CVE-2020-5303

The vulnerability has a CVSS base score of 3.1 (Low severity) with a high attack complexity. While it has a low availability impact, it requires user interaction for exploitation and can lead to denial of service.

Technical Details of CVE-2020-5303

Tendermint's denial-of-service vulnerability can be better understood through its technical aspects.

Vulnerability Description

Tendermint does not limit the number of P2P connection requests, leading to uncontrolled memory allocation.
The activeIDs map in Tendermint can grow indefinitely, causing memory exhaustion.

Affected Systems and Versions

Affected versions include >= 0.32.0, < 0.32.10, >= 0.33.0, < 0.33.3, and < 0.31.12 of Tendermint.

Exploitation Mechanism

Attackers can create numerous connection attempts, exploiting the uncontrolled memory allocation and causing the node to panic.

Mitigation and Prevention

Protecting systems from CVE-2020-5303 requires immediate actions and long-term security practices.

Immediate Steps to Take

Update Tendermint to versions 0.33.3 or 0.32.10, where the vulnerability is patched.
Monitor memory usage and connections for unusual spikes.

Long-Term Security Practices

Implement network-level protections to detect and block malicious connection attempts.
Regularly review and update security configurations to prevent similar vulnerabilities.

Patching and Updates

Apply security patches promptly to mitigate the risk of denial-of-service attacks.