# CVE-2021-44228: Apache Log4j2 - RCE

> Live exploitation tracking for CVE-2021-44228 by the CrowdSec Live Exploit Tracker, built from real-world attack data crowdsourced from CrowdSec's global network.

Page: https://tracker.crowdsec.net/cves/CVE-2021-44228

## Key facts

- **Exploitation phase:** Background Noise. Continuous low-level scanning or exploitation attempts are observed, mostly opportunistic and automated.
- **CVSS score:** 10.0
- **Public exploit available:** Yes
- **Affected products:** Apache Log4j2
- **Weaknesses:** CWE-917 (Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection'))

## Description

Apache Log4j2 2.0-beta9 through 2.15.0 (excluding security releases 2.12.2, 2.12.3, and 2.3.1) 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. From version 2.16.0 (along with 2.12.2, 2.12.3, and 2.3.1), this functionality has been completely removed. Note that this vulnerability is specific to log4j-core and does not affect log4net, log4cxx, or other Apache Logging Services projects.

## CrowdSec analysis

[CVE-2021-44228](https://euvd.enisa.europa.eu/vulnerability/CVE-2021-44228) is a critical remote code execution vulnerability in Apache Log4j2, often referred to as “Log4Shell.” It allows attackers to exploit JNDI lookups within log messages, enabling arbitrary code execution when crafted data is logged by affected systems.

CrowdSec has been tracking this vulnerability and its exploits since 10th of December 2021.

CrowdSec network data shows that most actors exploiting CVE-2021-44228 rely on broad, untargeted scans with minimal filtering. The activity is largely automated and opportunistic in nature.
Telemetry from the CrowdSec network also shows that exploitation activity for CVE-2021-44228 remains steady week-over-week. Attack volumes are consistent with long-term trends, indicating sustained interest from threat actors. CVE-2021-44228 continues to be an active part of the threat landscape and will likely remain this way for the forseeable future.

Observed attacks typically involve injection patterns in the request path that contain variations of `${jndi:`, reflecting the core technique used to trigger the remote code execution condition.

## Timeline

- 2021-12-10: CVE Published. CVE-2021-44228 is published to NVD.
- 2021-12-10: Rule Released. CrowdSec releases a rule to detect CVE-2021-44228 exploitation attempts against the CrowdSec Network.
- 2021-12-10: CrowdSec First Seen. CrowdSec observes in-the-wild exploitation of CVE-2021-44228 for the first time.
- 2021-12-10: CISA KEV. CVE-2021-44228 is added to the Known Exploited Vulnerabilities catalog by CISA.
- 2021-12-24: CISA Remediation Deadline. Expiration of the CISA remediation deadline as described in [BOD 22-01](https://www.cisa.gov/news-events/directives/bod-22-01-reducing-significant-risk-known-exploited-vulnerabilities).

## References

- https://security.netapp.com/advisory/ntap-20211210-0007/
- https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0032
- https://www.oracle.com/security-alerts/alert-cve-2021-44228.html
- https://lists.debian.org/debian-lts-announce/2021/12/msg00007.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VU57UJDCFIASIO35GC55JMKSRXJMCDFM/
- https://www.kb.cert.org/vuls/id/930724
- https://cert-portal.siemens.com/productcert/pdf/ssa-661247.pdf
- https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00646.html
- https://cert-portal.siemens.com/productcert/pdf/ssa-714170.pdf
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/M5CSVUNV4HWZZXGOKNSK6L7RPM7BOKIB/
- https://cert-portal.siemens.com/productcert/pdf/ssa-397453.pdf
- https://cert-portal.siemens.com/productcert/pdf/ssa-479842.pdf
- https://www.oracle.com/security-alerts/cpujan2022.html
- https://github.com/cisagov/log4j-affected-db
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://github.com/nu11secur1ty/CVE-mitre/tree/main/CVE-2021-44228
- https://www.nu11secur1ty.com/2021/12/cve-2021-44228.html
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-44228.yaml

## Live exploitation data

The [Live Exploit Tracker page](https://tracker.crowdsec.net/cves/CVE-2021-44228) follows observed exploitation activity for CVE-2021-44228. [Request an API key](https://tracker.crowdsec.net/request-api-key) for full access to its exploitation timeline, attacking IP addresses and blocklists.