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TrojanDownloader:PowerShell/NitSky.A
Aliases: No associated aliases
Summary
This threat represents PowerShell cmdlets which try to download the CobaltStrike Beacon payload from remote malicious servers. These are associated with prior exploitation of the remote code execution vulnerability CVE-2021-44228 (also referred to as “Log4Shell”) in the Log4j component of Apache. This vulnerability affects Java-based applications that use Log4j 2.
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Microsoft Defender Antivirus automatically removes threats as they are detected. If you have cloud-delivered protection, your device gets the latest defenses against new and unknown threats. If you don't have this feature enabled, update your antimalware definitions and run a full scan to remove this threat.
- Confirm that this server has Apache and the Log4j component installed.
- Check for possible post-exploitation activities, such as unusual behavior from users with elevated privileges or suspicious spawned processes.
- Stop suspicious processes, isolate affected devices, decommission compromised accounts or reset passwords, block IP addresses and URLs, and install security updates. Update the Log4j component to log4j-2.17.0 or ensure that the device is set to start with log4j2.formatMsgNoLookups set to True.
- Contact your incident response team, or contact Microsoft support for investigation and remediation services.
You can also visit our advanced troubleshooting page or search the Microsoft virus and malware community for more help.
