CVE-2021-45046

It was found that the fix to address CVE-2021-44228 in Apache Log4j 2.15.0 was incomplete in certain non-default configurations. This could allows attackers with control over Thread Context Map (MDC) input data when the logging configuration uses a non-default Pattern Layout with either a Context Lookup (for example, $${ctx:loginId}) or a Thread Context Map pattern (%X, %mdc, or %MDC) to craft malicious input data using a JNDI Lookup pattern resulting in an information leak and remote code execution in some environments and local code execution in all environments. Log4j 2.16.0 (Java 8) and 2.12.2 (Java 7) fix this issue by removing support for message lookup patterns and disabling JNDI functionality by default.

Impact

The fix to address CVE-2021-44228 in Apache Log4j 2.15.0 was incomplete in certain non-default configurations. This could allow attackers with control over Thread Context Map (MDC) input data when the logging configuration uses a non-default Pattern Layout with either a Context Lookup (for example, $${ctx:loginId}) or a Thread Context Map pattern (%X, %mdc, or %MDC) to craft malicious input data using a JNDI Lookup pattern resulting in a remote code execution (RCE) attack.

Affected packages

Only the org.apache.logging.log4j:log4j-core package is directly affected by this vulnerability. The org.apache.logging.log4j:log4j-api should be kept at the same version as the org.apache.logging.log4j:log4j-core package to ensure compatability if in use.

Mitigation

Log4j 2.16.0 fixes this issue by removing support for message lookup patterns and disabling JNDI functionality by default. This issue can be mitigated in prior releases (< 2.16.0) by removing the JndiLookup class from the classpath (example: zip -q -d log4j-core-*.jar org/apache/logging/log4j/core/lookup/JndiLookup.class).

Log4j 2.15.0 restricts JNDI LDAP lookups to localhost by default. Note that previous mitigations involving configuration such as to set the system property log4j2.formatMsgNoLookups to true do NOT mitigate this specific vulnerability.

Log4j is a tool to help the programmer output log statements to a variety of output targets.

Security Fix(es):

It was found that the fix to address CVE-2021-44228 in Apache Log4j 2.15.0 was incomplete in certain non-default configurations. This could allows attackers with control over Thread Context Map (MDC) input data when the logging configuration uses a non-default Pattern Layout with either a Context Lookup (for example, $${ctx:loginId}) or a Thread Context Map pattern (%X, %mdc, or %MDC) to craft malicious input data using a JNDI Lookup pattern resulting in a denial of service (DOS) attack. Log4j 2.15.0 makes a best-effort attempt to restrict JNDI LDAP lookups to localhost by default. Log4j 2.16.0 fixes this issue by removing support for message lookup patterns and disabling JNDI functionality by default.(CVE-2021-45046)

Log4j is a tool to help the programmer output log statements to a variety of output targets.

Security Fix(es):

Apache Log4j2 versions 2.0-alpha1 through 2.16.0 (excluding 2.12.3) 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 and 2.12.3.(CVE-2021-45105) It was found that the fix to address CVE-2021-44228 in Apache Log4j 2.15.0 was incomplete in certain non-default configurations. This could allows attackers with control over Thread Context Map (MDC) input data when the logging configuration uses a non-default Pattern Layout with either a Context Lookup (for example, $${ctx:loginId}) or a Thread Context Map pattern (%X, %mdc, or %MDC) to craft malicious input data using a JNDI Lookup pattern resulting in a denial of service (DOS) attack. Log4j 2.15.0 makes a best-effort attempt to restrict JNDI LDAP lookups to localhost by default. Log4j 2.16.0 fixes this issue by removing support for message lookup patterns and disabling JNDI functionality by default.(CVE-2021-45046) The details of a high-risk vulnerability in Apache Log4j2 have been disclosed. Attackers can use the vulnerability to execute code remotely. Some reports carry suspected POC, Apache Log4j2 is a Java-based logging tool. This tool rewrites the Log4j framework and introduces a large number of rich features. The log framework is widely used in business system development to record log information. In most cases, developers may write error messages caused by user input into the log. The trigger condition of this vulnerability is that as long as the data input by external users will be recorded in the log, it can cause remote code execution.(CVE-2021-44228)

Log4j is a tool to help the programmer output log statements to a variety of output targets.

Security Fix(es):

It was found that the fix to address CVE-2021-44228 in Apache Log4j 2.15.0 was incomplete in certain non-default configurations. This could allows attackers with control over Thread Context Map (MDC) input data when the logging configuration uses a non-default Pattern Layout with either a Context Lookup (for example, $${ctx:loginId}) or a Thread Context Map pattern (%X, %mdc, or %MDC) to craft malicious input data using a JNDI Lookup pattern resulting in an information leak and remote code execution in some environments and local code execution in all environments. Log4j 2.16.0 (Java 8) and 2.12.2 (Java 7) fix this issue by removing support for message lookup patterns and disabling JNDI functionality by default.(CVE-2021-45046)

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.(CVE-2021-45105)

Apache Log4j2 versions 2.0-beta7 through 2.17.0 (excluding security fix releases 2.3.2 and 2.12.4) are vulnerable to a remote code execution (RCE) attack when a configuration uses a JDBC Appender with a JNDI LDAP data source URI when an attacker has control of the target LDAP server. This issue is fixed by limiting JNDI data source names to the java protocol in Log4j2 versions 2.17.1, 2.12.4, and 2.3.2.(CVE-2021-44832)

It was found that the fix to address CVE-2021-44228 in Apache Log4j 2.15.0 was incomplete in certain non-default configurations. This could allows attackers with control over Thread Context Map (MDC) input data when the logging configuration uses a non-default Pattern Layout with either a Context Lookup (for example, $${ctx:loginId}) or a Thread Context Map pattern (%X, %mdc, or %MDC) to craft malicious input data using a JNDI Lookup pattern resulting in an information leak and remote code execution in some environments and local code execution in all environments. Log4j 2.16.0 (Java 8) and 2.12.2 (Java 7) fix this issue by removing support for message lookup patterns and disabling JNDI functionality by default.

TuxCare rebuilt org.apache.logging.log4j:log4j-core to address 3 CVEs. Fixed in 2.11.0-tuxcare.2.

TuxCare rebuilt org.apache.logging.log4j:log4j-core to address 3 CVEs. Fixed in 2.5-tuxcare.2.

It was found that the fix to address CVE-2021-44228 in Apache Log4j 2.15.0 was incomplete in certain non-default configurations. This could allows attackers with control over Thread Context Map (MDC) input data when the logging configuration uses a non-default Pattern Layout with either a Context Lookup (for example, $${ctx:loginId}) or a Thread Context Map pattern (%X, %mdc, or %MDC) to craft malicious input data using a JNDI Lookup pattern resulting in a denial of service (DOS) attack. Log4j 2.15.0 makes a best-effort attempt to restrict JNDI LDAP lookups to localhost by default. Log4j 2.16.0 fixes this issue by removing support for message lookup patterns and disabling JNDI functionality by default (CVE-2021-45046).

This update for log4j fixes the following issue:

• Previously published fixes for log4jshell turned out to be incomplete. Upstream has followed up on the original patch for CVE-2021-44228 with several additional changes (LOG4J2-3198, LOG4J2-3201, LOG4J2-3208, and LOG4J2-3211) that are included in this update. Since the totality of those patches is pretty much equivalent to an update to the latest version of log4j, we did update the package's tarball from version 2.13.0 to 2.16.0 instead of trying to apply those patches to the old version. This change brings in a new dependency on 'jakarta-servlet' and a version update of 'disruptor'. [bsc#1193743, CVE-2021-45046]

This update was imported from SUSE:SLE-15-SP2:Update.

This update for log4j fixes the following issue:

CVE-2021-44228: The previously published fix by upstream turned out to be incomplete. Therefore, upstream has recommended disabling JNDI support in log4j by default to be completely sure that this vulnerability cannot be exploited.

This update implements that recommendation and disables JNDI support by default. [bsc#1193611, CVE-2021-44228]

CVE-2021-45046: A Thread Context Message Pattern and Context Lookup Pattern vulnerable to a denial of service attack is also fixed by disabling JNDI support by default (bsc#1193743)

This update for log4j fixes the following issue:

• Previously published fixes for log4jshell turned out to be incomplete. Upstream has followed up on the original patch for CVE-2021-44228 with several additional changes (LOG4J2-3198, LOG4J2-3201, LOG4J2-3208, and LOG4J2-3211) that are included in this update. Since the totality of those patches is pretty much equivalent to an update to the latest version of log4j, we did update the package's tarball from version 2.13.0 to 2.16.0 instead of trying to apply those patches to the old version. This change brings in a new dependency on 'jakarta-servlet' and a version update of 'disruptor'. [bsc#1193743, CVE-2021-45046]

These are all security issues fixed in the log4j-2.16.0-2.1 package on the GA media of openSUSE Tumbleweed.

It was found that the fix to address CVE-2021-44228 in Apache Log4j 2.15.0 was incomplete in certain non-default configurations. An attacker could use this vulnerability to cause a denial of service. Please see the following link for more information: https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/Log4Shell