Cross-source coverage

T1102.001 / ATT&CK

Web Service: Dead Drop Resolver

8 rules across 2 sources.

Showing atomic-IOC rules · back to the default

From MITRE ATT&CK 19.2

Adversaries may use an existing, legitimate external Web service to host information that points to additional command and control (C2) infrastructure. Adversaries may post content, known as a dead drop resolver, on Web services with embedded (and often obfuscated/encoded) domains or IP addresses. Once infected, victims will reach out to and be redirected by these resolvers.

Popular websites and social media acting as a mechanism for C2 may give a significant amount of cover due to the likelihood that hosts within a network are already communicating with them prior to a compromise. Using common services, such as those offered by Google or Twitter, makes it easier for adversaries to hide in expected noise. Web service providers commonly use SSL/TLS encryption, giving adversaries an added level of protection.

Use of a dead drop resolver may also protect back-end C2 infrastructure from discovery through malware binary analysis while also enabling operational resiliency (since this infrastructure may be dynamically changed).

Platforms
ESXi · Linux · macOS · Windows
Telemetry
WinEventLog:Sysmonetw:Microsoft-Windows-NDIS-PacketCaptureauditd:SYSCALLNSM:Flowmacos:unifiedlogmacos:osqueryesxi:vobdNSM:Firewall

How MITRE says to detect it DET0058

Detection Strategy for Web Service: Dead Drop Resolver

Windows Analytic 0158

Detection of a process or script that accesses a common web service to retrieve content containing obfuscated indicators of a secondary C2 server (dead drop resolver behavior).

  • WinEventLog:Sysmon EventCode=3, 22
  • etw:Microsoft-Windows-NDIS-PacketCapture TLS Handshake/Network Flow

Linux Analytic 0159

Detection of a process or script that accesses a common web service to retrieve content containing obfuscated indicators of a secondary C2 server (dead drop resolver behavior).

  • auditd:SYSCALL connect
  • NSM:Flow HTTP/TLS Logs

macOS Analytic 0160

Detection of a process or script that accesses a common web service to retrieve content containing obfuscated indicators of a secondary C2 server (dead drop resolver behavior).

  • macos:unifiedlog subsystem: com.apple.network
  • macos:osquery process_events/socket_events

ESXi Analytic 0161

Detection of a process or script that accesses a common web service to retrieve content containing obfuscated indicators of a secondary C2 server (dead drop resolver behavior).

  • esxi:vobd Network Events
  • NSM:Firewall Outbound Connections

View on attack.mitre.org ↗

SigmaHQ/sigma

4 rules
Detection Severity Format
PwnDrp Access Critical Sigma
New Connection Initiated To Potential Dead Drop Resolver Domain High Sigma
Raw Paste Service Access High Sigma
Network Connection Initiated To AzureWebsites.NET By Non-Browser Process Medium Sigma

elastic/detection-rules

4 rules
Detection Severity Format
Google Calendar C2 via Script Interpreter High Elastic TOML
Potential Etherhiding C2 via Blockchain Connection High Elastic TOML
Connection to Commonly Abused Web Services Low Elastic TOML
DNS Request to Suspicious Top Level Domain Low Elastic TOML

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