|Platform||Windows Server 2003, Windows Server 2008, Windows Server 2012, Windows XP, Windows 7, Windows 8, Windows Server 2003 R2, Windows Server 2008 R2, Windows Server 2012 R2, Windows Vista, Windows 8.1, Linux, Windows 10, MacOS, OS X|
|Data Sources||File monitoring, Process monitoring, Binary file metadata|
|Defense Bypassed||Whitelisting by file name or path|
Masquerading occurs when an executable, legitimate or malicious, is placed in a commonly trusted location (such as C:\Windows\System32) or named with a common name (such as "explorer.exe" or "svchost.exe") to bypass tools that trust executables by relying on file name or path. An adversary may even use a renamed copy of a legitimate utility, such as rundll32.exe.1 Masquerading also may be done to deceive defenders and system administrators into thinking a file is benign by associating the name with something that is thought to be legitimate.
- The file name AcroRD32.exe, a legitimate process name for Adobe's Acrobat Reader, was used by APT1 as a name for malware.2
- APT32 has used hidden or non-printing characters to help masquerade file names on a system, such as appending a Unicode no-break space character to a legitimate service name.3
- Carbanak malware names itself "svchost.exe," which is the name of the Windows shared service host program.4
- FIN7 has created a scheduled task named “AdobeFlashSync” to establish persistence.5
- Patchwork installed its payload in the startup programs folder as "Baidu Software Update." The group also adds its second stage payload to the startup programs as “Net Monitor."6
- Poseidon Group tools attempt to spoof anti-virus processes as a means of self-defense.7
- admin@338 actors used the following command to rename one of their tools to a benign file name:
ren "%temp%\upload" audiodg.exe8
- ChChes copies itself to an .exe file with a filename that is likely intended to imitate Norton Antivirus but has several letters reversed (e.g. notron.exe).9
- If installing itself as a service fails, Elise instead writes itself as a file named svchost.exe saved in %APPDATA%\Microsoft\Network.10
- HTTPBrowser's installer contains a malicious file named navlu.dll to decrypt and run the RAT. navlu.dll is also the name of a legitimate Symantec DLL.11
- Mis-Type saves itself as a file named msdtc.exe, which is also the name of the legitimate Microsoft Distributed Transaction Coordinator service.1213
- Misdat saves itself as a file named msdtc.exe, which is also the name of the legitimate Microsoft Distributed Transaction Coordinator service.1213
- Nidiran can create a new service named msamger (Microsoft Security Accounts Manager), which mimics the legitimate Microsoft database by the same name.1415
- OLDBAIT installs itself in
%ALLUSERPROFILE%\\Application Data\Microsoft\MediaPlayer\updatewindws.exe; the directory name is missing a space and the file name is missing the letter "o."16
- OwaAuth uses the filename owaauth.dll, which is a legitimate file that normally resides in
%ProgramFiles%\Microsoft\Exchange Server\ClientAccess\Owa\Auth\; the malicious file by the same name is saved in
- In one instance, menuPass added PlugX as a service with a display name of "Corel Writing Tools Utility."18
- The Remsec loader implements itself with the name Security Support Provider, a legitimate Windows function. Various Remsec .exe files mimic legitimate file names used by Microsoft, Symantec, Kaspersky, Hewlett-Packard, and VMWare.1920 Remsec also disguised malicious modules using similar filenames as custom network encryption software on victims.20
- S-Type may save itself as a file named msdtc.exe, which is also the name of the legitimate Microsoft Distributed Transaction Coordinator service.1213
- Shamoon creates a new service named “ntssrv” that attempts to appear legitimate; the service's display name is “Microsoft Network Realtime Inspection Service” and its description is “Helps guard against time change attempts targeting known and newly discovered vulnerabilities in network time protocols.”21
- To establish persistence, SslMM identifies the Start Menu Startup directory and drops a link to its own executable disguised as an “Office Start,” “Yahoo Talk,” “MSN Gaming Z0ne,” or “MSN Talk” shortcut.22
- USBStealer mimics a legitimate Russian program called USB Disk Security.23
- A Winnti implant file was named ASPNET_FILTER.DLL, mimicking the legitimate ASP.NET ISAPI filter DLL with the same name.24
- ZLib mimics the resource version information of legitimate Realtek Semiconductor, Nvidia, or Synaptics modules.12
When creating security rules, avoid exclusions based on file name or file path. Require signed binaries. Use file system access controls to protect folders such as C:\Windows\System32. Use tools that restrict program execution via whitelisting by attributes other than file name.
Identify potentially malicious software that may look like a legitimate program based on name and location, and audit and/or block it by using whitelisting25 tools like AppLocker2627 or Software Restriction Policies28 where appropriate.29
Collect file hashes; file names that do not match their expected hash are suspect. Perform file monitoring; files with known names but in unusual locations are suspect. Likewise, files that are modified outside of an update or patch are suspect.
If file names are mismatched between the binary name on disk and the binary's resource section, this is a likely indicator that a binary was renamed after it was compiled. Collecting and comparing disk and resource filenames for binaries could provide useful leads, but may not always be indicative of malicious activity.1
- Ewing, P. (2016, October 31). How to Hunt: The Masquerade Ball. Retrieved October 31, 2016.
- Mandiant. (n.d.). Appendix C (Digital) - The Malware Arsenal. Retrieved July 18, 2016.
- Carr, N.. (2017, May 14). Cyber Espionage is Alive and Well: APT32 and the Threat to Global Corporations. Retrieved June 18, 2017.
- Kaspersky Lab's Global Research and Analysis Team. (2015, February). CARBANAK APT THE GREAT BANK ROBBERY. Retrieved March 3, 2015.
- Gorelik, M.. (2017, June 9). FIN7 Takes Another Bite at the Restaurant Industry. Retrieved July 13, 2017.
- Cymmetria. (2016). Unveiling Patchwork - The Copy-Paste APT. Retrieved August 3, 2016.
- Kaspersky Lab's Global Research and Analysis Team. (2016, February 9). Poseidon Group: a Targeted Attack Boutique specializing in global cyber-espionage. Retrieved March 16, 2016.
- FireEye Threat Intelligence. (2015, December 1). China-based Cyber Threat Group Uses Dropbox for Malware Communications and Targets Hong Kong Media Outlets. Retrieved December 4, 2015.
- PwC and BAE Systems. (2017, April). Operation Cloud Hopper: Technical Annex. Retrieved April 13, 2017.
- Falcone, R., et al.. (2015, June 16). Operation Lotus Blossom. Retrieved February 15, 2016.
- Desai, D.. (2015, August 14). Chinese cyber espionage APT group leveraging recently leaked Hacking Team exploits to target a Financial Services Firm. Retrieved January 26, 2016.
- Gross, J. (2016, February 23). Operation Dust Storm. Retrieved September 19, 2017.
- Microsoft. (2011, January 12). Distributed Transaction Coordinator. Retrieved February 25, 2016.
- Sponchioni, R.. (2016, March 11). Backdoor.Nidiran. Retrieved August 3, 2016.
- Microsoft. (2006, October 30). How to use the SysKey utility to secure the Windows Security Accounts Manager database. Retrieved August 3, 2016.
- FireEye. (2015). APT28: A WINDOW INTO RUSSIA’S CYBER ESPIONAGE OPERATIONS?. Retrieved August 19, 2015.
- Dell SecureWorks Counter Threat Unit Threat Intelligence. (2015, August 5). Threat Group-3390 Targets Organizations for Cyberespionage. Retrieved January 25, 2016.
- FireEye iSIGHT Intelligence. (2017, April 6). APT10 (MenuPass Group): New Tools, Global Campaign Latest Manifestation of Longstanding Threat. Retrieved June 29, 2017.
- Symantec Security Response. (2016, August 8). Backdoor.Remsec indicators of compromise. Retrieved August 17, 2016.
- Kaspersky Lab's Global Research & Analysis Team. (2016, August 9). The ProjectSauron APT. Retrieved August 17, 2016.
- Falcone, R.. (2016, November 30). Shamoon 2: Return of the Disttrack Wiper. Retrieved January 11, 2017.
- Baumgartner, K., Golovkin, M.. (2015, May). The MsnMM Campaigns: The Earliest Naikon APT Campaigns. Retrieved December 17, 2015.
- Calvet, J. (2014, November 11). Sednit Espionage Group Attacking Air-Gapped Networks. Retrieved January 4, 2017.
- Cap, P., et al. (2017, January 25). Detecting threat actors in recent German industrial attacks with Windows Defender ATP. Retrieved February 8, 2017.
- Beechey, J. (2010, December). Application Whitelisting: Panacea or Propaganda?. Retrieved November 18, 2014.
- Tomonaga, S. (2016, January 26). Windows Commands Abused by Attackers. Retrieved February 2, 2016.
- NSA Information Assurance Directorate. (2014, August). Application Whitelisting Using Microsoft AppLocker. Retrieved March 31, 2016.
- Corio, C., & Sayana, D. P. (2008, June). Application Lockdown with Software Restriction Policies. Retrieved November 18, 2014.
- Microsoft. (2012, June 27). Using Software Restriction Policies and AppLocker Policies. Retrieved April 7, 2016.