Web Service: Dead Drop Resolver
Other sub-techniques of Web Service (3)
| ID | Name |
|---|---|
| T1102.001 | Dead Drop Resolver |
| T1102.002 | Bidirectional Communication |
| T1102.003 | One-Way Communication |
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).
Procedure Examples
| Name | Description |
|---|---|
| APT41 |
APT41 used legitimate websites for C2 through dead drop resolvers (DDR), including GitHub, Pastebin, and Microsoft TechNet.[15] |
| BADNEWS |
BADNEWS collects C2 information via a dead drop resolver.[5][6][7] |
| BLACKCOFFEE |
BLACKCOFFEE uses Microsoft’s TechNet Web portal to obtain a dead drop resolver containing an encoded tag with the IP address of a command and control server.[3][4] |
| BRONZE BUTLER |
BRONZE BUTLER's MSGET downloader uses a dead drop resolver to access malicious payloads.[13] |
| MiniDuke |
Some MiniDuke components use Twitter to initially obtain the address of a C2 server or as a backup if no hard-coded C2 server responds.[1][2] |
| Patchwork |
Patchwork hides base64-encoded and encrypted C2 server locations in comments on legitimate websites.[14] |
| PlugX | |
| Rocke |
Rocke has used Pastebin to check the version of beaconing malware and redirect to another Pastebin hosting updated malware.[16] |
| RTM |
RTM has used an RSS feed on Livejournal to update a list of encrypted C2 server names. RTM has also hidden Pony C2 server IP addresses within transactions on the Bitcoin and Namecoin blockchain.[10][11][12] |
| RTM |
RTM has used an RSS feed on Livejournal to update a list of encrypted C2 server names.[10] |
| Xbash |
Xbash can obtain a webpage hosted on Pastebin to update its C2 domain list.[9] |
Mitigations
| Mitigation | Description |
|---|---|
| Network Intrusion Prevention |
Network intrusion detection and prevention systems that use network signatures to identify traffic for specific adversary malware can be used to mitigate activity at the network level. |
| Restrict Web-Based Content |
Web proxies can be used to enforce external network communication policy that prevents use of unauthorized external services. |
Detection
Host data that can relate unknown or suspicious process activity using a network connection is important to supplement any existing indicators of compromise based on malware command and control signatures and infrastructure or the presence of strong encryption. Packet capture analysis will require SSL/TLS inspection if data is encrypted. User behavior monitoring may help to detect abnormal patterns of activity.[17]
References
- F-Secure Labs. (2015, September 17). The Dukes: 7 years of Russian cyberespionage. Retrieved December 10, 2015.
- Kaspersky Lab's Global Research & Analysis Team. (2013, February 27). The MiniDuke Mystery: PDF 0-day Government Spy Assembler 0x29A Micro Backdoor. Retrieved April 5, 2017.
- FireEye Labs/FireEye Threat Intelligence. (2015, May 14). Hiding in Plain Sight: FireEye and Microsoft Expose Obfuscation Tactic. Retrieved January 22, 2016.
- FireEye. (2018, March 16). Suspected Chinese Cyber Espionage Group (TEMP.Periscope) Targeting U.S. Engineering and Maritime Industries. Retrieved April 11, 2018.
- Settle, A., et al. (2016, August 8). MONSOON - Analysis Of An APT Campaign. Retrieved September 22, 2016.
- Levene, B. et al.. (2018, March 7). Patchwork Continues to Deliver BADNEWS to the Indian Subcontinent. Retrieved March 31, 2018.
- Lunghi, D., et al. (2017, December). Untangling the Patchwork Cyberespionage Group. Retrieved July 10, 2018.
- Lancaster, T. and Idrizovic, E.. (2017, June 27). Paranoid PlugX. Retrieved July 13, 2017.
- Xiao, C. (2018, September 17). Xbash Combines Botnet, Ransomware, Coinmining in Worm that Targets Linux and Windows. Retrieved November 14, 2018.
- Faou, M. and Boutin, J. (2017, February). Read The Manual: A Guide to the RTM Banking Trojan. Retrieved March 9, 2017.
- Eisenkraft, K., Olshtein, A. (2019, October 17). Pony’s C&C servers hidden inside the Bitcoin blockchain. Retrieved June 15, 2020.
- Duncan, B., Harbison, M. (2019, January 23). Russian Language Malspam Pushing Redaman Banking Malware. Retrieved June 16, 2020.
- Counter Threat Unit Research Team. (2017, October 12). BRONZE BUTLER Targets Japanese Enterprises. Retrieved January 4, 2018.
- Kaspersky Lab's Global Research & Analysis Team. (2016, July 8). The Dropping Elephant – aggressive cyber-espionage in the Asian region. Retrieved August 3, 2016.
- Fraser, N., et al. (2019, August 7). Double DragonAPT41, a dual espionage and cyber crime operation APT41. Retrieved September 23, 2019.
- Anomali Labs. (2019, March 15). Rocke Evolves Its Arsenal With a New Malware Family Written in Golang. Retrieved April 24, 2019.
- Gardiner, J., Cova, M., Nagaraja, S. (2014, February). Command & Control Understanding, Denying and Detecting. Retrieved April 20, 2016.