Log4j zero-day gets security fix just as scans for vulnerable systems ramp up
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2021-44228 | JNDI Injection Remote Code Execution in Apache Log4j2 (Log4Shell) Apache Log4j2, an extremely widely used Java logging library, fails to protect its JNDI lookup feature against attacker-controlled JNDI-related endpoints (CWE-20, CWE-502), so crafted text processed by the logger causes the Java runtime to fetch and load attacker-supplied objects, leading to remote code execution. The flaw is triggered whenever attacker-controlled input reaches the logging API and is parsed for JNDI lookups, a pattern common in web servers and enterprise Java applications that log user-supplied fields such as headers or form values. Successful exploitation yields arbitrary code execution under the privileges of the affected application, giving attackers a foothold for lateral movement, data theft, and ransomware deployment. Any Java application or product that ships or bundles an affected Apache Log4j2 release is exposed, making this one of the most broadly deployed vulnerabilities ever disclosed. Exploitation is confirmed in the wild: CISA added it to the Known Exploited Vulnerabilities catalog on 2021-12-10 with known ransomware use, and EPSS assigns a 100% probability of exploitation within 30 days. Do: Inventory all Java applications and dependencies for Apache Log4j2 and apply the vendor's patched updates, or remove affected assets from the network, as required by CISA's KEV catalog. Where updates are not yet available, use the temporary mitigations in CISA's ED-22-02 recommended-mitigation guidance, such as disabling message lookups, only until patches are applied. Prioritize internet-facing and business-critical systems and hunt for exploitation activity given known ransomware use. | 10.0 | 100% | KEV ransomware PoC ×9 |
| masshundreds of millions of Java applications/devices, with hundreds of thousands of internet-exposed services |
Full article570 words · extracted from therecord.media · click to collapse
The Apache Software Foundation has released an emergency security update today to patch a zero-day vulnerability in Log4j, a Java library that provides logging capabilities. The patch—part of the 2.15.0 release—fixes a remote code execution vulnerability (CVE-2021-44228) disclosed yesterday on Twitter, complete with proof-of-concept code.
https://twitter.com/P0rZ9/status/1468949890571337731
The vulnerability, also nicknamed Log4Shell, can be exploited by forcing Java-based apps and servers, where the Log4j library was used, to log a specific string into their internal systems. When the app or server processes the logs, this string can force the vulnerable system to download and run a malicious script from an attacker-controlled domain, effectively taking over the vulnerable application/server, according to a technical breakdown published yesterday by security firm LunaSec. With a score of 10/10 on the CVSSv3 severity scale, Log4Shell is as bad as it gets in terms of security flaws, being both remotely exploitable and requiring little technical skill to execute. Discovered during a bug bounty engagement against Minecraft servers, the vulnerability is far more impactful than some might expect, primarily because of Log4j's near-ubiquitous presence in almost all major Java-based enterprise apps and servers. For example, Log4j is included with almost all the enterprise products released by the Apache Software Foundation, such as Apache Struts, Apache Flink, Apache Druid, Apache Flume, Apache Solr, Apache Flink, Apache Kafka, Apache Dubbo, and possibly many more. In addition, other open-source projects like Redis, ElasticSearch, Elastic Logstash, the NSA's Ghidra, and others also use it in some capacity or other. Naturally, all the companies that use any of these products are also indirectly vulnerable to the Log4Shell exploit, even if some of them may be aware of it or not. According to some research published yesterday, companies with servers confirmed to be vulnerable to Log4Shell attacks include the likes of Apple, Amazon, Twitter, Cloudflare, Steam, Tencent, Baidu, DIDI, JD, NetEase, and possibly thousands more. According to p0rz9, the Chinese security researcher who first posted the exploit code online, CVE-2021-44228 can only be abused if the log4j2.formatMsgNoLookups option in the library's configuration is set to false. In a conversation today, Heige, the founder and CEO of Chinese security firm KnownSec 404 Team and one of the first researchers to understand the vulnerability's impact, told The Record that today's Log4j 2.15.0 release basically sets this option to true in order to block attacks. Log4j users who update to the 2.15.0 version but then set this flag back to false will remain vulnerable to attacks. Similarly, Log4j users who can't update but set the flag to true can block attacks even on older versions. Unfortunately, this option is set to false by default in old releases, meaning that all past Log4j releases since 2.10.0, when this option was added, are vulnerable by default.
https://twitter.com/80vul/status/1468988170021011459
According to reports from security firms Bad Packets and Greynoise, multiple threat actors are already scanning for apps that may be vulnerable to the Log4Shell attack, meaning that server owners will most likely have a very small patch window at their disposal before servers start getting backdoored if they haven't been already.Enormous impact
Attacks can be blocked with a config change
No previous article
No new articles
Catalin Cimpanu
is a cybersecurity reporter who previously worked at ZDNet and Bleeping Computer, where he became a well-known name in the industry for his constant scoops on new vulnerabilities, cyberattacks, and law enforcement actions against hackers.
Text extracted automatically; images, tables and formatting may be missing. Original: https://therecord.media/log4j-zero-day-gets-security-fix-just-as-scans-for-vulnerable-systems-ramp-up