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Spearphishing Attachment

Spearphishing attachment is a specific variant of spearphishing. Spearphishing attachment is different from other forms of spearphishing in that it employs the use of malware attached to an email. All forms of spearphishing are electronically delivered social engineering targeted at a specific individual, company, or industry. In this scenario, adversaries attach a file to the spearphishing email and usually rely upon User Execution to gain execution.

There are many options for the attachment such as Microsoft Office documents, executables, PDFs, or archived files. Upon opening the attachment (and potentially clicking past protections), the adversary's payload exploits a vulnerability or directly executes on the user's system. The text of the spearphishing email usually tries to give a plausible reason why the file should be opened, and may explain how to bypass system protections in order to do so. The email may also contain instructions on how to decrypt an attachment, such as a zip file password, in order to evade email boundary defenses. Adversaries frequently manipulate file extensions and icons in order to make attached executables appear to be document files, or files exploiting one application appear to be a file for a different one.

ID: T1193

Tactic: Initial Access

Platform:  Windows, macOS, Linux

Data Sources:  File monitoring, Packet capture, Network intrusion detection system, Detonation chamber, Email gateway, Mail server

CAPEC ID:  CAPEC-163

Version: 1.0

Examples

NameDescription
APT19

APT19 sent spearphishing emails with malicious attachments in RTF and XLSM formats to deliver initial exploits.[1]

APT28

APT28 sent spearphishing emails containing malicious Microsoft Office attachments.[2][3][4][5]

APT29

APT29 has used spearphishing with an attachment to deliver files with exploits to initial victims.[6]

APT32

APT32 sends emails to victims with a malicious executable disguised as a document or spreadsheet displaying a fake icon.[7]

APT37

APT37 delivers malware using spearphishing emails with malicious HWP attachments.[8][9]

BRONZE BUTLER

BRONZE BUTLER used spearphishing emails with malicious Microsoft Word attachments to infect victims.[10]

Cobalt Group

Cobalt Group has sent spearphishing emails with various attachment types to corporate and personal email accounts of victim organizations. Attachment types have included .rtf, .doc, .xls, archives containing LNK files, and password protected archives containing .exe and .scr executables.[11][12][13][14][15][16]

DarkHydrus

DarkHydrus has sent spearphishing emails with password-protected RAR archives containing malicious Excel Web Query files (.iqy). The group has also sent spearphishing emails that contained malicious Microsoft Office documents that use the "attachedTemplate" technique to load a template from a remote server.[17][18][19]

Dragonfly 2.0

Dragonfly 2.0 used spearphishing with Microsoft Office attachments to target victims.[20][21]

Elderwood

Elderwood has delivered zero-day exploits and malware to victims via targeted emails containing malicious attachments.[22][23]

FIN7

FIN7 sent spearphishing emails with either malicious Microsoft Documents or RTF files attached.[24][25]

FIN8

FIN8 has distributed targeted emails containing Word documents with embedded malicious macros.[26][27][28]

Gorgon Group

Gorgon Group sent emails to victims with malicious Microsoft Office documents attached.[29]

Lazarus Group

Lazarus Group has targeted victims with spearphishing emails containing malicious Microsoft Word documents.[30]

Leviathan

Leviathan has sent spearphishing emails with malicious attachments, including .rtf, .doc, and .xls files.[31]

Magic Hound

Magic Hound sent malicious attachments to victims over email, including an Excel spreadsheet containing macros to download Pupy.[32]

menuPass

menuPass has sent malicious Office documents via email as part of spearphishing campaigns as well as executables disguised as documents.[33][34][35]

MuddyWater

MuddyWater has compromised third parties and used compromised accounts to send spearphishing emails with targeted attachments to recipients.[36][37]

OilRig

OilRig has sent spearphising emails with malicious attachments to potential victims using compromised and/or spoofed email accounts.[38][39]

Patchwork

Patchwork has used spearphishing with an attachment to deliver files with exploits to initial victims.[40][41][42][43]

PLATINUM

PLATINUM has sent spearphishing emails with attachments to victims as its primary initial access vector.[44]

Rancor

Rancor has attached a malicious document to an email to gain initial access.[45]

TA459

TA459 has targeted victims using spearphishing emails with malicious Microsoft Word attachments.[46]

Mitigation

Network intrusion prevention systems and systems designed to scan and remove malicious email attachments can be used to block activity. Solutions can be signature and behavior based, but adversaries may construct attachments in a way to avoid these systems.

Block unknown or unused attachments by default that should not be transmitted over email as a best practice to prevent some vectors, such as .scr, .exe, .pif, .cpl, etc. Some email scanning devices can open and analyze compressed and encrypted formats, such as zip and rar that may be used to conceal malicious attachments in Obfuscated Files or Information.

Because this technique involves user interaction on the endpoint, it's difficult to fully mitigate. However, there are potential mitigations. Users can be trained to identify social engineering techniques and spearphishing emails. To prevent the attachments from executing, application whitelisting can be used. Anti-virus can also automatically quarantine suspicious files.

Detection

Network intrusion detection systems and email gateways can be used to detect spearphishing with malicious attachments in transit. Detonation chambers may also be used to identify malicious attachments. Solutions can be signature and behavior based, but adversaries may construct attachments in a way to avoid these systems.

Anti-virus can potentially detect malicious documents and attachments as they're scanned to be stored on the email server or on the user's computer. Endpoint sensing or network sensing can potentially detect malicious events once the attachment is opened (such as a Microsoft Word document or PDF reaching out to the internet or spawning Powershell.exe) for techniques such as Exploitation for Client Execution and Scripting.

References

  1. Ahl, I. (2017, June 06). Privileges and Credentials: Phished at the Request of Counsel. Retrieved May 17, 2018.
  2. Lee, B, et al. (2018, February 28). Sofacy Attacks Multiple Government Entities. Retrieved March 15, 2018.
  3. Falcone, R. (2018, March 15). Sofacy Uses DealersChoice to Target European Government Agency. Retrieved June 4, 2018.
  4. Lee, B., Falcone, R. (2018, June 06). Sofacy Group’s Parallel Attacks. Retrieved June 18, 2018.
  5. Mueller, R. (2018, July 13). Indictment - United States of America vs. VIKTOR BORISOVICH NETYKSHO, et al. Retrieved September 13, 2018.
  6. F-Secure Labs. (2015, September 17). The Dukes: 7 years of Russian cyberespionage. Retrieved December 10, 2015.
  7. Foltýn, T. (2018, March 13). OceanLotus ships new backdoor using old tricks. Retrieved May 22, 2018.
  8. FireEye. (2018, February 20). APT37 (Reaper): The Overlooked North Korean Actor. Retrieved March 1, 2018.
  9. Mercer, W., Rascagneres, P. (2018, January 16). Korea In The Crosshairs. Retrieved May 21, 2018.
  10. DiMaggio, J. (2016, April 28). Tick cyberespionage group zeros in on Japan. Retrieved July 16, 2018.
  11. Svajcer, V. (2018, July 31). Multiple Cobalt Personality Disorder. Retrieved September 5, 2018.
  12. Positive Technologies. (2017, August 16). Cobalt Strikes Back: An Evolving Multinational Threat to Finance. Retrieved September 5, 2018.
  13. Positive Technologies. (2016, December 16). Cobalt Snatch. Retrieved October 9, 2018.
  14. Matveeva, V. (2017, August 15). Secrets of Cobalt. Retrieved October 10, 2018.
  15. Mesa, M, et al. (2017, June 1). Microsoft Word Intruder Integrates CVE-2017-0199, Utilized by Cobalt Group to Target Financial Institutions. Retrieved October 10, 2018.
  16. Klijnsma, Y.. (2017, November 28). Gaffe Reveals Full List of Targets in Spear Phishing Attack Using Cobalt Strike Against Financial Institutions. Retrieved October 10, 2018.
  17. Falcone, R., et al. (2018, July 27). New Threat Actor Group DarkHydrus Targets Middle East Government. Retrieved August 2, 2018.
  18. Falcone, R. (2018, August 07). DarkHydrus Uses Phishery to Harvest Credentials in the Middle East. Retrieved August 10, 2018.
  19. Unit 42. (2017, December 15). Unit 42 Playbook Viewer. Retrieved December 20, 2017.
  20. US-CERT. (2018, March 16). Alert (TA18-074A): Russian Government Cyber Activity Targeting Energy and Other Critical Infrastructure Sectors. Retrieved June 6, 2018.
  21. US-CERT. (2017, October 20). Alert (TA17-293A): Advanced Persistent Threat Activity Targeting Energy and Other Critical Infrastructure Sectors. Retrieved November 2, 2017.
  22. O'Gorman, G., and McDonald, G.. (2012, September 6). The Elderwood Project. Retrieved February 15, 2018.
  23. Clayton, M.. (2012, September 14). Stealing US business secrets: Experts ID two huge cyber 'gangs' in China. Retrieved February 15, 2018.
  1. Carr, N., et al. (2017, April 24). FIN7 Evolution and the Phishing LNK. Retrieved April 24, 2017.
  2. Department of Justice. (2018, August 01). HOW FIN7 ATTACKED AND STOLE DATA. Retrieved August 24, 2018.
  3. Bohannon, D. & Carr N. (2017, June 30). Obfuscation in the Wild: Targeted Attackers Lead the Way in Evasion Techniques. Retrieved February 12, 2018.
  4. Kizhakkinan, D. et al.. (2016, May 11). Threat Actor Leverages Windows Zero-day Exploit in Payment Card Data Attacks. Retrieved February 12, 2018.
  5. Elovitz, S. & Ahl, I. (2016, August 18). Know Your Enemy: New Financially-Motivated & Spear-Phishing Group. Retrieved February 26, 2018.
  6. Falcone, R., et al. (2018, August 02). The Gorgon Group: Slithering Between Nation State and Cybercrime. Retrieved August 7, 2018.
  7. Sherstobitoff, R. (2018, March 08). Hidden Cobra Targets Turkish Financial Sector With New Bankshot Implant. Retrieved May 18, 2018.
  8. Axel F, Pierre T. (2017, October 16). Leviathan: Espionage actor spearphishes maritime and defense targets. Retrieved February 15, 2018.
  9. Counter Threat Unit Research Team. (2017, July 27). The Curious Case of Mia Ash: Fake Persona Lures Middle Eastern Targets. Retrieved February 26, 2018.
  10. PwC and BAE Systems. (2017, April). Operation Cloud Hopper: Technical Annex. Retrieved April 13, 2017.
  11. FireEye iSIGHT Intelligence. (2017, April 6). APT10 (MenuPass Group): New Tools, Global Campaign Latest Manifestation of Longstanding Threat. Retrieved June 29, 2017.
  12. Matsuda, A., Muhammad I. (2018, September 13). APT10 Targeting Japanese Corporations Using Updated TTPs. Retrieved September 17, 2018.
  13. Lancaster, T.. (2017, November 14). Muddying the Water: Targeted Attacks in the Middle East. Retrieved March 15, 2018.
  14. Singh, S. et al.. (2018, March 13). Iranian Threat Group Updates Tactics, Techniques and Procedures in Spear Phishing Campaign. Retrieved April 11, 2018.
  15. Lee, B., Falcone, R. (2018, February 23). OopsIE! OilRig Uses ThreeDollars to Deliver New Trojan. Retrieved July 16, 2018.
  16. Lee, B., Falcone, R. (2018, July 25). OilRig Targets Technology Service Provider and Government Agency with QUADAGENT. Retrieved August 9, 2018.
  17. Cymmetria. (2016). Unveiling Patchwork - The Copy-Paste APT. Retrieved August 3, 2016.
  18. Kaspersky Lab's Global Research & Analysis Team. (2016, July 8). The Dropping Elephant – aggressive cyber-espionage in the Asian region. Retrieved August 3, 2016.
  19. Lunghi, D., et al. (2017, December). Untangling the Patchwork Cyberespionage Group. Retrieved July 10, 2018.
  20. Meltzer, M, et al. (2018, June 07). Patchwork APT Group Targets US Think Tanks. Retrieved July 16, 2018.
  21. Windows Defender Advanced Threat Hunting Team. (2016, April 29). PLATINUM: Targeted attacks in South and Southeast Asia. Retrieved February 15, 2018.
  22. Ash, B., et al. (2018, June 26). RANCOR: Targeted Attacks in South East Asia Using PLAINTEE and DDKONG Malware Families. Retrieved July 2, 2018.
  23. Axel F. (2017, April 27). APT Targets Financial Analysts with CVE-2017-0199. Retrieved February 15, 2018.