Analytics Story: DarkCrystal RAT
Description
Leverage searches that allow you to detect and investigate unusual activities that might relate to the DcRat malware including ddos, spawning more process, botnet c2 communication, defense evasion and etc. The DcRat malware is known commercial backdoor that was first released in 2018. This tool was sold in underground forum and known to be one of the cheapest commercial RATs. DcRat is modular and bespoke plugin framework make it a very flexible option, helpful for a range of nefearious uses.
Why it matters
Adversaries may use this technique to maximize the impact on the target organization in operations where network wide availability interruption is the goal.
Correlation Search
1| tstats `security_content_summariesonly` min(_time) as firstTime max(_time) as lastTime sum(All_Risk.calculated_risk_score) as risk_score, count(All_Risk.calculated_risk_score) as risk_event_count, values(All_Risk.annotations.mitre_attack.mitre_tactic_id) as annotations.mitre_attack.mitre_tactic_id, dc(All_Risk.annotations.mitre_attack.mitre_tactic_id) as mitre_tactic_id_count, values(All_Risk.annotations.mitre_attack.mitre_technique_id) as annotations.mitre_attack.mitre_technique_id, dc(All_Risk.annotations.mitre_attack.mitre_technique_id) as mitre_technique_id_count, values(All_Risk.tag) as tag, values(source) as source, dc(source) as source_count from datamodel=Risk.All_Risk where source IN ("*Cmdline Tool Not Executed In CMD Shell*", "*Windows System Network Config Discovery Display DNS*", "*Local Account Discovery With Wmic*", "*Net Localgroup Discovery*", "*Create local admin accounts using net exe*", "*Local Account Discovery with Net*", "*Icacls Deny Command*", "*ICACLS Grant Command*", "*Windows Proxy Via Netsh*", "*Processes launching netsh*", "*Disabling Firewall with Netsh*", "*Windows System Network Connections Discovery Netsh*", "*Network Connection Discovery With Arp*", "*Windows System Discovery Using ldap Nslookup*", "*Windows System Shutdown CommandLine*") by All_Risk.risk_object All_Risk.risk_object_type All_Risk.annotations.mitre_attack.mitre_tactic | `drop_dm_object_name(All_Risk)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | where source_count >= 4 | `windows_common_abused_cmd_shell_risk_behavior_filter`
Detections
Data Sources
Name | Platform | Sourcetype | Source |
---|---|---|---|
CrowdStrike ProcessRollup2 | N/A | crowdstrike:events:sensor |
crowdstrike |
Powershell Script Block Logging 4104 | Windows | xmlwineventlog |
XmlWinEventLog:Microsoft-Windows-PowerShell/Operational |
Sysmon EventID 1 | Windows | xmlwineventlog |
XmlWinEventLog:Microsoft-Windows-Sysmon/Operational |
Sysmon EventID 11 | Windows | xmlwineventlog |
XmlWinEventLog:Microsoft-Windows-Sysmon/Operational |
Sysmon EventID 22 | Windows | xmlwineventlog |
XmlWinEventLog:Microsoft-Windows-Sysmon/Operational |
Sysmon EventID 23 | Windows | xmlwineventlog |
XmlWinEventLog:Microsoft-Windows-Sysmon/Operational |
Sysmon EventID 7 | Windows | xmlwineventlog |
XmlWinEventLog:Microsoft-Windows-Sysmon/Operational |
Windows Event Log Security 4688 | Windows | xmlwineventlog |
XmlWinEventLog:Security |
Windows Event Log TaskScheduler 200 | Windows | wineventlog |
WinEventLog:Microsoft-Windows-TaskScheduler/Operational |
References
- https://www.mandiant.com/resources/analyzing-dark-crystal-rat-backdoor
- https://malpedia.caad.fkie.fraunhofer.de/details/win.dcrat
Source: GitHub | Version: 1