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).
View in MITRE ATT&CK®| Capability ID | Capability Description | Mapping Type | ATT&CK ID | ATT&CK Name |
|---|---|---|---|---|
| AC-4 | Information Flow Enforcement | Protects | T1102.001 | Dead Drop Resolver |
| CA-7 | Continuous Monitoring | Protects | T1102.001 | Dead Drop Resolver |
| CM-2 | Baseline Configuration | Protects | T1102.001 | Dead Drop Resolver |
| CM-6 | Configuration Settings | Protects | T1102.001 | Dead Drop Resolver |
| CM-7 | Least Functionality | Protects | T1102.001 | Dead Drop Resolver |
| SC-7 | Boundary Protection | Protects | T1102.001 | Dead Drop Resolver |
| SI-3 | Malicious Code Protection | Protects | T1102.001 | Dead Drop Resolver |
| SI-4 | System Monitoring | Protects | T1102.001 | Dead Drop Resolver |
| action.malware.variety.Backdoor or C2 | Malware creates a remote control capability, but it's unclear if it's a backdoor for hacking or C2 for malware. Parent of 'C2' and 'Backdoor'. | related-to | T1102.001 | Web Service: Dead Drop Resolver |
| action.malware.variety.C2 | Malware creates Command and Control capability for malware. Child of 'Backdoor or C2'. | related-to | T1102.001 | Web Service: Dead Drop Resolver |