As security and development teams rushed to assess the now-notorious Log4Shell vulnerability published December 10 (CVE-2021-44228), another, more minor vulnerability was discovered in Log4j — CVE-2021-45046. To understand the newly-discovered vulnerability, it is important to get the full picture and background on the original Log4j issue.
Dec. 29: Updated to cover three additional CVEs: CVE-2021-4104, CVE-2021-44832, and CVE-2021-42550 (in logback as opposed to log4j). Dec. 22: A joint Cybersecurity Advisory was issued by multiple national cybersecurity agencies providing mitigation guidance on addressing vulnerabilities in Apache’s Log4j software library: CVE-2021-44228 (known as “Log4Shell”), CVE-2021-45046, and CVE-2021-45105. Dec. 17: Please note the emergency directive from CISA on Log4j.
Dec. 29: Updated to cover three additional CVEs: CVE-2021-4104, CVE-2021-44832, and CVE-2021-42550 (in logback as opposed to log4j). Dec. 22: A joint Cybersecurity Advisory was issued by multiple national cybersecurity agencies providing mitigation guidance on addressing vulnerabilities in Apache’s Log4j software library: CVE-2021-44228 (known as “Log4Shell”), CVE-2021-45046, and CVE-2021-45105. Dec. 17: Please note the emergency directive from CISA on Log4j.
While many organizations are patching the two recent Apache Log4j vulnerabilities (CVE-2021-44228 and CVE-2021-45046), attackers have been racing to exploit them to deliver malware, such as botnets, backdoors, and cryptominers. Among the threats delivered using Log4Shell exploits, a new ransomware family was found by Bitdefender: Khonsari.
The Apache Log4j vulnerability has been assigned the most critical cyber threat rating of CVSS 10. For a concise overview of the zero-day, and to learn how to secure your systems against its exploitation, all of the popular FAQs concerning this vulnerability have been conveniently compiled in this post.
Is it just me or is the announcement of a significant CVE becoming a holiday tradition? Discovered on December 9, 2021 by Minecraft players, the Apache Log4Shell vulnerability is a uniquely insidious because it infects servers which are traditionally well insulated from attacks and perceived as unreachable by an intruder and not at risk for CVEs. Log4Shell is an entirely different can of works that proves this assumption wrong.
We recently discussed some methods for detecting the Log4j exploit, and we’ve now developed another method that everyone running Zeek® or a Corelight sensor can use. Our new approach is based on the rarity of legitimate downloads of Java via LDAP. Zeek does not currently have a native LDAP protocol analyzer (though one is available if you are running Spicy). This will not stop you from detecting this exploit downloading Java over LDAP, though. To see how, read on.
In quick succession in December, The Apache Software Foundation released information on two critical vulnerabilities in its Log4j Java-based library. The first vulnerability CVE-2021-44228, also known as Log4Shell or LogJam, was reported as an unauthenticated remote code execution (RCE) vulnerability. By exploiting how the library logs error messages, it could lead to a complete system takeover.
