Synology-SA-21:30 Log4Shell

Abstract

None of Synology's products are affected as these vulnerabilities only affect products equipped with log4j 2.

Affected Products

Mitigation

None

Detail

• CVE-2021-44228

  • Severity: Not affected
  • CVSS3 Base Score: 0.0
  • CVSS3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N
  • Apache Log4j2 <=2.14.1 JNDI features used in configuration, log messages, and parameters do not protect against attacker controlled LDAP and other JNDI related endpoints. An attacker who can control log messages or log message parameters can execute arbitrary code loaded from LDAP servers when message lookup substitution is enabled. From log4j 2.15.0, this behavior has been disabled by default. In previous releases (>2.10) this behavior can be mitigated by setting system property "log4j2.formatMsgNoLookups" to “true” or it can be mitigated in prior releases (<2.10) by removing the JndiLookup class from the classpath (example: zip -q -d log4j-core-*.jar org/apache/logging/log4j/core/lookup/JndiLookup.class).

• CVE-2021-45046

  • Severity: Not affected
  • CVSS3 Base Score: 0.0
  • CVSS3 Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:N
  • 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 restricts JNDI LDAP lookups to localhost by default. Note that previous mitigations involving configuration such as to set the system property log4j2.noFormatMsgLookup to true do NOT mitigate this specific vulnerability. 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).

• CVE-2021-44832

  • Severity: Not affected
  • CVSS3 Base Score: 0.0
  • CVSS3 Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:N
  • 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.

Reference

• Apache Releases Log4j Version 2.15.0 to Address Critical RCE Vulnerability Under Exploitation
• CVE-2021-44228
• CVE-2021-45046
• CVE-2021-44832

Revision