By Shunichi Imano, James Slaughter, and Gergely Revay | December 21, 2021
FortiGuard Labs Threat Research Report
Affected Platforms: Any application and service that uses vulnerable version of Log4j2
Impacted Users: Any organization that uses vulnerable version of Log4j
Impact: Remote attackers gain control of the vulnerable systems
Severity Level: Critical
Thanks to Paolo Di Prodi and Arturo Erick Torres Cavazos, who helped contribute to this blog.
Beginning December 9th, most of the internet-connected world was forced to reckon with a critical new vulnerability discovered in the Apache Log4j framework deployed in countless servers. Officially labeled CVE-2021-44228, but colloquially known as “Log4Shell”, this vulnerability is both trivial to exploit and allows for full remote code execution on a target system. This has earned the vulnerability a CVSS score of 10 – the maximum.
On December 14th, the Apache Software Foundation revealed a second Log4j vulnerability (CVE-2021-45046). It was initially identified as a Denial-of-Service (DoS) vulnerability with a CVSS score of 3.7 and moderate severity. Things went from bad to worse on December 16th due to the discovery of information leaks and the remote code execution nature of the vulnerability. This promoted Apache to update the advisory and upgrade the CVSS score for this vulnerability to 9.0.
On December 18th, a third Log4J vulnerability was discovered (CVE-2021-45105 - Apache Log4j2 does not always protect against infinite recursion in lookup evaluation). This fix was released in response to a newly discovered vulnerability that makes Log4j susceptible to a Denial-of-Service attack (DoS).
On December 19th, a "wormable" variant of the Mirai IoT malware incorporating exploit code for CVE-2021-44228 was discovered. Various chatter on OSINT channels has discussed whether this is a "worm."
This blog describes what you need to know about the Apache Log4j vulnerabilities, including details, campaigns associated with Log4j, and an alleged “wormable” Mirai malware variant.