UPDATE — 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.”
The Apache Software Foundation (ASF) has pushed out a new fix for the Log4j logging utility after the previous patch for the recently disclosed Log4Shell exploit was deemed as “incomplete in certain non-default configurations.”
The second vulnerability — tracked as CVE-2021-45046 — is rated 3.7 out of a maximum of 10 on the CVSS rating system and affects all versions of Log4j from 2.0-beta9 through 2.12.1 and 2.13.0 through 2.15.0, which the project maintainers shipped last week to address a critical remote code execution vulnerability (CVE-2021-44228) that could be abused to infiltrate and take over systems.
The incomplete patch for CVE-2021-44228 could be abused to “craft malicious input data using a JNDI Lookup pattern resulting in a denial-of-service (DoS) attack,” the ASF said in a new advisory. The latest version of Log4j, 2.16.0 (for users requiring Java 8 or later), all but removes support for message lookups and disables JNDI by default, the component that’s at the heart of the vulnerability. Users requiring Java 7 are recommended to upgrade to Log4j release 2.12.2 when it becomes available.
“Dealing with CVE-2021-44228 has shown the JNDI has significant security issues,” Ralph Goers of the ASF explained. “While we have mitigated what we are aware of it would be safer for users to completely disable it by default, especially since the large majority are unlikely to be using it.”
JNDI, short for Java Naming and Directory Interface, is a Java API that enables applications coded in the programming language to look up data and resources such as LDAP servers. Log4Shell is resident in the Log4j library, an open-source, Java-based logging framework commonly incorporated into Apache web servers.
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