CVE-2020-24388 : Security Advisory and Response

An issue was discovered in the _send_secure_msg() function of yubihsm-shell through 2.0.2 that could lead to a denial of service attack.

Understanding CVE-2020-24388

This CVE identifies a vulnerability in the _send_secure_msg() function of yubihsm-shell through version 2.0.2.

What is CVE-2020-24388?

The vulnerability arises from the function's failure to validate the embedded length field of a message received from the device, potentially resulting in a crash of the running process. This flaw could be exploited by an attacker to cause a denial of service.

The Impact of CVE-2020-24388

The vulnerability could allow an attacker to crash the running process, leading to a denial of service condition.

Technical Details of CVE-2020-24388

This section provides technical details of the CVE.

Vulnerability Description

The _send_secure_msg() function in yubihsm-shell through 2.0.2 does not validate the embedded length field of a received message, leading to a potential denial of service through an oversized memcpy() call.

Affected Systems and Versions

Product: N/A
Vendor: N/A
Versions affected: yubihsm-shell through 2.0.2

Exploitation Mechanism

The vulnerability can be exploited by sending a specially crafted message to the affected function, triggering an oversized memcpy() call that crashes the process.

Mitigation and Prevention

Protect your systems from CVE-2020-24388 with the following steps:

Immediate Steps to Take

Update yubihsm-shell to a non-vulnerable version.
Monitor for any unusual activity that could indicate an ongoing attack.

Long-Term Security Practices

Regularly update software and firmware to patch known vulnerabilities.
Implement network segmentation to limit the impact of potential attacks.

Patching and Updates

Apply patches provided by the vendor to address the vulnerability in yubihsm-shell.