CVE-2021-45046: Apache Log4j2 Deserialization of Untrusted Data, actively exploited

Description

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.

CVSS 3.1 breakdown

Attack vectorNetwork

Attack complexityHigh

Privileges requiredNone

User interactionNone

ScopeChanged

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Affected products

Apache Log4j≥ 2.0.1 < 2.12.2 · ≥ 2.13.0 < 2.16.0 · 2.0

Cvat Computer Vision Annotation Toolall versions

Intel Audio Development Kitall versions

Intel Datacenter Managerall versions

Intel Genomics Kernel Libraryall versions

Intel Oneapiall versions

Intel Secure Device Onboardall versions

Intel Sensor Solution Firmware Development Kitall versions

Intel System Debuggerall versions

Intel System Studioall versions

Siemens Captial< 2019.1 · 2019.1

Siemens Comosall versions

Siemens Desigo Cc Advanced Reports4.0 · 4.1 · 4.2 · 5.0

Siemens Desigo Cc Info Center5.0 · 5.1

Siemens E-car Operation Center< 2021-12-13

Siemens Energy Engage3.1

Siemens Energyip8.5 · 8.6 · 8.7 · 9.0

Siemens Energyip Prepay3.7 · 3.8

Siemens Gma-manager< 8.6.2j-398

Siemens Head-end System Universal Device Integration Systemall versions

Siemens Industrial Edge Managementall versions

Siemens Industrial Edge Management Hub< 2021-12-13

Siemens Logo! Soft Comfortall versions

Siemens Mendixall versions

Remediation

Fixed in

Apache Log4j≥ 2.12.2

Siemens Captial≥ 2019.1

Siemens E-car Operation Center≥ 2021-12-13

Siemens Gma-manager≥ 8.6.2j-398

Siemens Industrial Edge Management Hub≥ 2021-12-13

Siemens Mindsphere≥ 2021-12-11

Siemens Navigator≥ 2021-12-13

Siemens Solid Edge Harness Design≥ 2020

Siemens Spectrum Power 4≥ 4.70

Siemens Spectrum Power 7≥ 2.30

Patch & vendor advisories

References

https://cert-portal.siemens.com/productcert/pdf/ssa-397453.pdfThird Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-479842.pdfThird Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-661247.pdfThird Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-714170.pdfThird Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EOKPQGV24RRBBI4TBZUDQMM4MEH7MXCY/Mailing ListRelease Notes
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SIG7FZULMNK2XF6FZRU4VWYDQXNMUGAJ/Mailing ListRelease Notes
https://logging.apache.org/log4j/2.x/security.htmlMitigationRelease NotesVendor Advisory
https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0032Third Party Advisory
https://security.gentoo.org/glsa/202310-16Third Party Advisory
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-log4j-qRuKNEbdThird Party Advisory

and 12 more references

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

Frequently asked

Is CVE-2021-45046 being actively exploited?

Yes. CVE-2021-45046 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 1 May 2023. It has been used in ransomware campaigns.

How severe is CVE-2021-45046?

CVE-2021-45046 has a CVSS 3.1 base score of 9.0, rated critical. EPSS estimates a 100.0% probability of exploitation.

Which products are affected by CVE-2021-45046?

Affected products include Apache Log4j, Cvat Computer Vision Annotation Tool, Intel Audio Development Kit, Intel Datacenter Manager, Intel Genomics Kernel Library, and 19 more.

How do I fix CVE-2021-45046?

Upgrade affected software to a fixed version, for example Apache Log4j 2.12.2, Siemens Captial 2019.1, Siemens E-car Operation Center 2021-12-13 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2021-45046 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, Secuno flags any affected asset as top-priority automatically. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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