Apache Log4j2 - RCE (CVE-2021-44228)
Active exploitation with moderate targeting or momentum
Prioritize patching. Consider deploying a blocklist for affected CVEs.
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.
psychologyCrowdSec Analysis
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.
Exploitation Timeline
groupSignals collected from the CrowdSec community network.
| Event | Date |
|---|---|
| CVE Published | 2021-12-10 |
| Rule Released | 2021-12-10 |
| CrowdSec First Seen | 2021-12-10 |
| CISA KEV | 2021-12-10 |
| CISA Remediation Deadline | 2021-12-24 |
Active Attackers
Unique IPs observed exploiting this CVE in the last 14 days.
Remediation & Protection
codeAPI Access
Retrieve full intelligence data for CVE-2021-44228
External 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