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Apache Issues 3rd Patch to Fix New High

highVulnerability exploited in the wildimportance 60CVE-2021-45105CVE-2021-45046CVE-2021-44228

Vulnerabilities mentionedAll →

CVEVulnerabilityCVSSEPSSFlagsAffectedExposurePublished
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.

10.0100% KEV ransomware PoC ×9
  • Apache Log4j2
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.

9.0100% KEV ransomware
  • Apache Log4j2 Log4j 2.x; per Apache advisory, 2.0-beta9 through 2.15.0 (and 2.16.0 in some non-default configurations), fixed in 2.17.0 and in 2.12.3/2.3.1 for older branches
massmillions of Java deployments worldwide, with hundreds of thousands of internet-exposed services observed in public scans during the Log4Shell campaign
CVE-2021-45105
Apache Log4j2 versions 2.0-alpha1 through 2.16.0 (excluding 2.12.3 and 2.3.1) did not protect from uncontrolled recursion from self-referential lookups.

Apache Log4j2 versions 2.0-alpha1 through 2.16.0 (excluding 2.12.3 and 2.3.1) did not protect from uncontrolled recursion from self-referential lookups. This allows an attacker with control over Thread Context Map data to cause a denial of service when a crafted string is interpreted. This issue was fixed in Log4j 2.17.0, 2.12.3, and 2.3.1.

NVD description · AI analysis pending
5.9100%
  • apache log4j
  • apache cloud manager
  • apache debian linux
  • +1 more
Full article572 words · extracted from thehackernews.com · click to collapse

Ravie LakshmananDec 18, 2021

The issues with Log4j continued to stack up as the Apache Software Foundation (ASF) on Friday rolled out yet another patch — version 2.17.0 — for the widely used logging library that could be exploited by malicious actors to stage a denial-of-service (DoS) attack.

Tracked as CVE-2021-45105 (CVSS score: 7.5), the new vulnerability affects all versions of the tool from 2.0-beta9 to 2.16.0, which the open-source nonprofit shipped earlier this week to remediate a second flaw that could result in remote code execution (CVE-2021-45046), which, in turn, stemmed from an "incomplete" fix for CVE-2021-44228, otherwise called the Log4Shell vulnerability.

"Apache Log4j2 versions 2.0-alpha1 through 2.16.0 did not protect from uncontrolled recursion from self-referential lookups," the ASF explained in a revised advisory. "When the logging configuration uses a non-default Pattern Layout with a Context Lookup (for example, $${ctx:loginId}), attackers with control over Thread Context Map (MDC) input data can craft malicious input data that contains a recursive lookup, resulting in a StackOverflowError that will terminate the process."

Hideki Okamoto of Akamai Technologies and an anonymous vulnerability researcher have been credited with reporting the flaw. Log4j versions 1.x, however, are not affected by CVE-2021-45105.

It's worth pointing out that the severity score of CVE-2021-45046, originally classified as a DoS bug, has since been revised from 3.7 to 9.0, to reflect the fact that an attacker could abuse the vulnerability to send a specially crafted string that leads to "information leak and remote code execution in some environments and local code execution in all environments," corroborating a previous report from security researchers at Praetorian.

The project maintainers also noted that Log4j versions 1.x have reached end of life and are no longer supported, and that security flaws uncovered in the utility after August 2015 will not be fixed, urging users to upgrade to Log4j 2 to get the latest fixes.

The fixes are the latest in what's a highly dynamic situation as the U.S. Cybersecurity and Infrastructure Security Agency (CISA) issued an emergency directive mandating federal civilian departments and agencies to immediately patch their internet-facing systems for the Apache Log4j vulnerabilities by December 23, 2021, citing that the weaknesses pose an "unacceptable risk."

The development also comes as the Log4j flaws have emerged as a lucrative attack vector and a focal point for exploitation by multiple threat actors, including nation-backed hackers from the likes of China, Iran, North Korea, and Turkey as well as the Conti ransomware gang, to carry out an array of follow-on malicious activities. This marks the first time the vulnerability has come under the radar of a sophisticated crimeware cartel.

"The current exploitation led to multiple use cases through which the Conti group tested the possibilities of utilizing the Log4j 2 exploit," AdvIntel researchers said. "the criminals pursued targeting specific vulnerable Log4j 2 VMware vCenter [servers] for lateral movement directly from the compromised network resulting in vCenter access affecting U.S. and European victim networks from the pre-existent Cobalt Strike sessions."

Among the others to leverage the bug are cryptocurrency miners, botnets, remote access trojans, initial access brokers, and a new ransomware strain called Khonsari. Israeli security firm Check Point said it recorded over 3.7 million exploitation attempts to date, with 46% of those intrusions made by known malicious groups.

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