Guidance for preventing, detecting, and hunting for CVE-2021-44228 Log4j 2 exploitation in SAP Systems
The Log4j is a Java-based logging audit framework within Apache. Apache Log4j2 2.14.1 and below are susceptible to a remote code execution (RCE) vulnerability. An attacker can leverage this vulnerability to take full control of a targeted machine.
This module is a prerequisite for other software, which means it can be found in many products, including those from SAP SE, and is trivial to exploit. It is critical that organizations take immediate action to inventory their systems and prioritize remediation.
- Impacted Versions
- Apache Log4j 2.x <= 2.15.0-rc1
- CVSS: 10 (CRITICAL)
Detection vs. Prevention
Microsoft’s Threat Intelligence team, which is responsible for the evaluation and threat analysis of security vulnerabilities and malware, has published an initial analysis of the Log4Shell vulnerability (CVE-2021-44228) in the Log4J logging library. There it emphasizes: “Every system with Log4J must be considered attacked meanwhile”.
Specifically, Microsoft’s assessment states, “Because the attack vectors through which this vulnerability can be exploited are broad and fully deploying remediation in large environments will take time, we recommend defenders look for signs of post-exploitation rather than relying entirely on prevention.”
Log4j usage in SAP
There are several ways to answer the question of using Log4j in SAP products. On the one hand, you can wait for the release of the manufacturer itself. On the other hand, there are also innovative solutions like the one from one of our partners, the SAP security experts from NO-MONKEY.
The team of NO-MONKEY has presented in their GitHub repository (https://github.com/NO-MONKEY/log4j_use_in_sap) an impressive analysis that shows how common the use of the vulnerable component Log4j is in the SAP product portfolio. They have published an elastic search, looking for the vulnerable component in SAP’s public help pages.
Although, the results do not try to claim completeness, it is a valuable source that proves the wide usage.
SAP SE does not leave their customers alone! The SAP Global Security has published a document named: “SAP’s Response to CVE-2021-44228 Apache Log4j 2”
The document is available for SAP customers with access to the SAP Support Portal via the following link: https://support.sap.com/content/dam/support/en_us/library/ssp/my-support/trust-center/sap-tc-01-5025.pdf
Attack vector and observed activity
We quote from a posting on the Microsoft Security Blog. The blog writes under the headline “Nation-state activity” the following,
“MSTIC has also observed the CVE-2021-44228 vulnerability is being used by multiple tracked nation-state activity groups originating from China, Iran, North Korea, and Turkey. This activity ranges from experimentation during development, integration of the vulnerability to in-the-wild payload deployment, and exploitation against targets to achieve the actor’s objectives.”
Furthermore, the Microsoft Security Team and independent Security publishers confirm that the Log4J vulnerability has been successfully used to deploy ransomware.
The vast majority of traffic observed by Microsoft remains mass scanners by both attackers and security researchers.
At this point, we recommend assuming that an affected system has already been infiltrated. Consequently, the following applies:
- increase your log levels to detect anomalies
- Activate available log sources in SAP if they are not already active
- Check SAP’s publications regularly
- Prioritize SAP systems that communicate with untrusted networks. These should be especially monitored!
- If you use NG Firewall i.e a FortiGate NG with an Intrusion Prevention System, update the IPS signature
Using SecurityBridge Threat Detection, you already have a great foundation to detect anomaly behavior within your SAP Application Stack. Our experts recommend paying special attention to any events that signals:
- Privilege escalation
- Data exfiltration
- Remote activities (RCE, remote function calls)
Use SecurityBridge Security & Compliance Monitor to understand the overall security posture and act in accordance with the classification of data processed by the individual instance.