CVE-2020-12783 : Security Advisory and Response

Exim through 4.93 has an out-of-bounds read in the SPA authenticator that could result in SPA/NTLM authentication bypass.

Understanding CVE-2020-12783

Exim through version 4.93 is vulnerable to an out-of-bounds read in the SPA authenticator, potentially leading to authentication bypass.

What is CVE-2020-12783?

The vulnerability in Exim could allow attackers to bypass SPA/NTLM authentication by exploiting the out-of-bounds read in specific authentication files.

The Impact of CVE-2020-12783

This vulnerability could be exploited by malicious actors to bypass authentication mechanisms, potentially leading to unauthorized access to systems utilizing Exim.

Technical Details of CVE-2020-12783

Exim through version 4.93 is susceptible to an out-of-bounds read vulnerability in the SPA authenticator.

Vulnerability Description

The vulnerability exists in the auths/spa.c and auths/auth-spa.c files, allowing for potential SPA/NTLM authentication bypass.

Affected Systems and Versions

Product: Not applicable
Vendor: Not applicable
Versions affected: All versions up to 4.93

Exploitation Mechanism

Attackers can exploit this vulnerability to bypass SPA/NTLM authentication, potentially gaining unauthorized access to systems.

Mitigation and Prevention

Immediate action is crucial to mitigate the risks posed by CVE-2020-12783.

Immediate Steps to Take

Update Exim to version 4.94 or later to address the vulnerability.
Monitor for any unauthorized access or unusual activities on the system.

Long-Term Security Practices

Regularly update and patch Exim and other software to prevent vulnerabilities.
Implement strong authentication mechanisms and access controls to enhance system security.

Patching and Updates

Apply patches and updates provided by Exim to ensure the security of the system.