Software Packing

Software packing is a method of compressing or encrypting an executable. Packing an executable changes the file signature in an attempt to avoid signature-based detection. Most decompression techniques decompress the executable code in memory.

Utilities used to perform software packing are called packers. Example packers are MPRESS and UPX. A more comprehensive list of known packers is available, [1] but adversaries may create their own packing techniques that do not leave the same artifacts as well-known packers to evade defenses.

ID: T1045

Tactic: Defense Evasion

Platform:  Windows

Data Sources:  Binary file metadata

Defense Bypassed:  Signature-based detection, Anti-virus, Heuristic detection

CAPEC ID:  CAPEC-570

Version: 1.0

Examples

NameDescription
APT29

APT29 used UPX to pack files.[2]

APT3

APT3 has been known to pack their tools.[3]

APT32

APT32 uses UPX to pack their macOS backdoor.[4]

APT38

APT38 has used several code packing methods such as Themida, Enigma, VMProtect, and Obsidium, to pack their implants.[5]

APT39

APT39 has repacked a modified version of Mimikatz to thwart anti-virus detection.[6]

Astaroth

Astaroth uses a software packer called Pe123\RPolyCryptor.[7]

China Chopper

China Chopper's client component is packed with UPX.[8]

Dark Caracal

Dark Caracal has used UPX to pack Bandook[9]

DarkComet

DarkComet has the option to compress its payload using UPX or MPRESS.[10]

Daserf

A version of Daserf uses the MPRESS packer.[11]

Elderwood

Elderwood has packed malware payloads before delivery to victims.[12]

Emotet

Emotet has used custom packers to protect its payloads.[13]

FinFisher

A FinFisher variant uses a custom packer.[14][15]

GreyEnergy

GreyEnergy is packed for obfuscation.[16]

Group5

Group5 packed an executable by base64 encoding the PE file and breaking it up into numerous lines.[17]

H1N1

H1N1 uses a custom packing algorithm.[18]

jRAT

jRAT payloads have been packed.[19]

Night Dragon

Night Dragon is known to use software packing in its tools.[20]

OopsIE

OopsIE uses the SmartAssembly obfuscator to pack an embedded .Net Framework assembly used for C2.[21]

Patchwork

A Patchwork payload was packed with UPX.[22]

SeaDuke

SeaDuke has been packed with the UPX packer.[23]

TrickBot

TrickBot leverages a custom packer to obfuscate its functionality.[24]

Trojan.Karagany

Trojan.Karagany samples sometimes use common binary packers such as UPX and Aspack on top of a custom Delphi binary packer.[25]

Uroburos

Uroburos uses a custom packer.[26]

VERMIN

VERMIN is initially packed.[27]

yty

yty packs a plugin with UPX.[28]

Zebrocy

Zebrocy's Delphi variant was packed with UPX.[29]

ZeroT

Some ZeroT DLL files have been packed with UPX.[30]

Mitigation

Ensure updated virus definitions. Create custom signatures for observed malware. Employ heuristic-based malware detection.

Identify and prevent execution of potentially malicious software that may have been packed by using whitelisting [31] tools like AppLocker [32] [33] or Software Restriction Policies [34] where appropriate. [35]

Detection

Use file scanning to look for known software packers or artifacts of packing techniques. Packing is not a definitive indicator of malicious activity, because legitimate software may use packing techniques to reduce binary size or to protect proprietary code.

References

  1. Executable compression. (n.d.). Retrieved December 4, 2014.
  2. Dunwoody, M. and Carr, N.. (2016, September 27). No Easy Breach DerbyCon 2016. Retrieved October 4, 2016.
  3. Korban, C, et al. (2017, September). APT3 Adversary Emulation Plan. Retrieved January 16, 2018.
  4. Dumont, R.. (2019, April 9). OceanLotus: macOS malware update. Retrieved April 15, 2019.
  5. FireEye. (2018, October 03). APT38: Un-usual Suspects. Retrieved November 6, 2018.
  6. Hawley et al. (2019, January 29). APT39: An Iranian Cyber Espionage Group Focused on Personal Information. Retrieved February 19, 2019.
  7. Salem, E. (2019, February 13). ASTAROTH MALWARE USES LEGITIMATE OS AND ANTIVIRUS PROCESSES TO STEAL PASSWORDS AND PERSONAL DATA. Retrieved April 17, 2019.
  8. Lee, T., Hanzlik, D., Ahl, I. (2013, August 7). Breaking Down the China Chopper Web Shell - Part I. Retrieved March 27, 2015.
  9. Blaich, A., et al. (2018, January 18). Dark Caracal: Cyber-espionage at a Global Scale. Retrieved April 11, 2018.
  10. Kujawa, A. (2018, March 27). You dirty RAT! Part 1: DarkComet. Retrieved November 6, 2018.
  11. Chen, J. and Hsieh, M. (2017, November 7). REDBALDKNIGHT/BRONZE BUTLER’s Daserf Backdoor Now Using Steganography. Retrieved December 27, 2017.
  12. O'Gorman, G., and McDonald, G.. (2012, September 6). The Elderwood Project. Retrieved February 15, 2018.
  13. Trend Micro. (2019, January 16). Exploring Emotet's Activities . Retrieved March 25, 2019.
  14. FinFisher. (n.d.). Retrieved December 20, 2017.
  15. Kaspersky Lab's Global Research & Analysis Team. (2017, October 16). BlackOasis APT and new targeted attacks leveraging zero-day exploit. Retrieved February 15, 2018.
  16. Cherepanov, A. (2018, October). GREYENERGY A successor to BlackEnergy. Retrieved November 15, 2018.
  17. Scott-Railton, J., et al. (2016, August 2). Group5: Syria and the Iranian Connection. Retrieved September 26, 2016.
  18. Reynolds, J.. (2016, September 13). H1N1: Technical analysis reveals new capabilities. Retrieved September 26, 2016.
  1. Kamluk, V. & Gostev, A. (2016, February). Adwind - A Cross-Platform RAT. Retrieved April 23, 2019.
  2. McAfee® Foundstone® Professional Services and McAfee Labs™. (2011, February 10). Global Energy Cyberattacks: “Night Dragon”. Retrieved February 19, 2018.
  3. Lee, B., Falcone, R. (2018, February 23). OopsIE! OilRig Uses ThreeDollars to Deliver New Trojan. Retrieved July 16, 2018.
  4. Kaspersky Lab's Global Research & Analysis Team. (2016, July 8). The Dropping Elephant – aggressive cyber-espionage in the Asian region. Retrieved August 3, 2016.
  5. Grunzweig, J.. (2015, July 14). Unit 42 Technical Analysis: Seaduke. Retrieved August 3, 2016.
  6. Salinas, M., Holguin, J. (2017, June). Evolution of Trickbot. Retrieved July 31, 2018.
  7. Symantec Security Response. (2014, July 7). Dragonfly: Cyberespionage Attacks Against Energy Suppliers. Retrieved April 8, 2016.
  8. Symantec. (2015, January 26). The Waterbug attack group. Retrieved April 10, 2015.
  9. Lancaster, T., Cortes, J. (2018, January 29). VERMIN: Quasar RAT and Custom Malware Used In Ukraine. Retrieved July 5, 2018.
  10. Schwarz, D., Sopko J. (2018, March 08). Donot Team Leverages New Modular Malware Framework in South Asia. Retrieved June 11, 2018.
  11. Lee, B., Falcone, R. (2018, December 12). Dear Joohn: The Sofacy Group’s Global Campaign. Retrieved April 19, 2019.
  12. Huss, D., et al. (2017, February 2). Oops, they did it again: APT Targets Russia and Belarus with ZeroT and PlugX. Retrieved April 5, 2018.
  13. Beechey, J. (2010, December). Application Whitelisting: Panacea or Propaganda?. Retrieved November 18, 2014.
  14. Tomonaga, S. (2016, January 26). Windows Commands Abused by Attackers. Retrieved February 2, 2016.
  15. NSA Information Assurance Directorate. (2014, August). Application Whitelisting Using Microsoft AppLocker. Retrieved March 31, 2016.
  16. Corio, C., & Sayana, D. P. (2008, June). Application Lockdown with Software Restriction Policies. Retrieved November 18, 2014.
  17. Microsoft. (2012, June 27). Using Software Restriction Policies and AppLocker Policies. Retrieved April 7, 2016.