Hackers Begin Exploiting Second Log4j Vulnerability as a Third Flaw Emerges
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 | |
| CVE-2021-45046 | Remote Code Execution in Apache Log4j2 via Incomplete Log4Shell Fix CVE-2021-45046 is a remote code execution and information disclosure flaw in Apache Log4j2 (CWE-917) that resulted from an incomplete fix to CVE-2021-44228 (Log4Shell), leaving the Thread Context Lookup Pattern vulnerable in certain non-default configurations. It is triggered when an application logs attacker-controlled data using layouts or patterns that perform Thread Context (MDC) lookups, allowing crafted lookup expressions to be evaluated against untrusted input. A successful attacker can achieve remote code execution, or potentially information disclosure, on the affected service. Any deployment of Apache Log4j2 that relies on the affected non-default lookup configurations is exposed, which given Log4j2's ubiquity in Java applications and embedded products means a very large installed base. Exploitation is confirmed: the flaw is in CISA KEV (added 2023-05-01) with known ransomware use, and EPSS assigns a 100% probability of exploitation within 30 days. Do: Upgrade Log4j2 to 2.17.0 or later per vendor instructions (or 2.12.3/2.3.1 for the legacy 2.12/2.3 branches), since the 2.16.0 fix was itself incomplete in some non-default configurations. Where upgrading is not immediately possible, remove the JndiLookup class from the Log4j2 jar or disable lookup processing, and audit applications and dependencies that bundle Log4j2 while following the CISA KEV required action to apply vendor updates. | 9.0 | 100% | KEV ransomware |
| massmillions of Java deployments worldwide, with hundreds of thousands of internet-exposed services observed in public scans during the Log4Shell campaign |
Full article556 words · extracted from thehackernews.com · click to collapse
Ravie LakshmananDec 16, 2021
Web infrastructure company Cloudflare on Wednesday revealed that threat actors are actively attempting to exploit a second bug disclosed in the widely used Log4j logging utility, making it imperative that customers move quickly to install the latest version as a barrage of attacks continues to pummel unpatched systems with a variety of malware.
The new vulnerability, assigned the identifier CVE-2021-45046, makes it possible for adversaries to carry out denial-of-service (DoS) attacks and follows disclosure from the Apache Software Foundation (ASF) that the original fix for the remote code execution bug — CVE-2021-44228 aka Log4Shell — was "incomplete in certain non-default configurations." The issue has since been addressed in Log4j version 2.16.0.
"This vulnerability is actively being exploited and anyone using Log4j should update to version 2.16.0 as soon as possible, even if you have previously updated to 2.15.0," Cloudflare's Andre Bluehs and Gabriel Gabor said.
Even more troublingly, researchers at security firm Praetorian warned of a third separate security weakness in Log4j version 2.15.0 that can "allow for exfiltration of sensitive data in certain circumstances." Additional technical details of the flaw have been withheld to prevent further exploitation, but it's not immediately clear if this has been already addressed in version 2.16.0.
"2.16 disables JNDI lookups by default and — as a result — is the safest version of Log4j2 that we're aware of," Anthony Weems, principal security engineer at Praetorian, told The Hacker News. When reached for a response, the Apache Logging Services Project Management Committee (PMC) confirmed that "We have been in contact with the engineer from Praetorian to fully understand the nature and scope of the problem."
The latest development comes as advanced persistent threat groups from China, Iran, North Korea, and Turkey, counting the likes of Hafnium and Phosphorus, have jumped into the fray to operationalize the vulnerability and discover and continue exploiting as many susceptible systems as possible for follow-on attacks. Over 1.8 million attempts to exploit the Log4j vulnerability have been recorded so far.
Microsoft Threat Intelligence Center (MSTIC) said it also observed access brokers leveraging the Log4Shell flaw to gain initial access to target networks that were then sold to other ransomware affiliates. In addition, dozens of malware families that run the gamut from cryptocurrency coin miners and remote access trojans to botnets and web shells have been identified taking advantage of this shortcoming to date.
While it's common for threat actors to make efforts to exploit newly disclosed vulnerabilities before they're remediated, the Log4j flaw underscores the risks arising from software supply chains when a key piece of software is used within a broad range of products across several vendors and deployed by their customers around the world.
"This cross-cutting vulnerability, which is vendor-agnostic and affects both proprietary and open-source software, will leave a wide swathe of industries exposed to remote exploitation, including electric power, water, food and beverage, manufacturing, transportation, and more," industrial cybersecurity firm Dragos noted.
"As network defenders close off more simplistic exploit paths and advanced adversaries incorporate the vulnerability in their attacks, more sophisticated variations of Log4j exploits will emerge with a higher likelihood of directly impacting Operational Technology networks," the company added.
Found this article interesting? Follow us on Google News, Twitter and LinkedIn to read more exclusive content we post.
Text extracted automatically; images, tables and formatting may be missing. Original: https://thehackernews.com/2021/12/hackers-begin-exploiting-second-log4j.html