#VU58976 Code Injection in Apache Log4j - CVE-2021-45046

Description

The vulnerability allows a remote attacker to compromise the affected system.

The vulnerability exists due to incomplete patch in Apache Log4j 2.15.0 for a code injection vulnerability #VU58816 (CVE-2021-44228) in certain non-default configurations. A remote attacker with control over Thread Context Map (MDC) input data when the logging configuration uses a non-default Pattern Layout with either a Context Lookup (for example, $${ctx:loginId}) or a Thread Context Map pattern (%X, %mdc, or %MDC) can pass malicious data using a JNDI Lookup pattern and perform a denial of service (DoS) attack, exfiltrate data or execute arbitrary code.

Later discovery demonstrates a remote code execution on macOS but no other tested environments.

Remediation

External links

• http://www.openwall.com/lists/oss-security/2021/12/14/4
• https://logging.apache.org/log4j/2.x/security.html
• https://www.cve.org/CVERecord?id=CVE-2021-44228
• https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00646.html
• https://issues.apache.org/jira/browse/LOG4J2-3221