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OwaAuth

OwaAuth is a Web shell and credential stealer deployed to Microsoft Exchange servers that appears to be exclusively used by Threat Group-3390. [1]

ID: S0072
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Type: MALWARE
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Platforms: Windows
Version: 1.2
Created: 31 May 2017
Last Modified: 17 June 2021
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Enterprise Layer
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Techniques Used

Domain ID Name Use
Enterprise T1071 .001 Application Layer Protocol: Web Protocols

OwaAuth uses incoming HTTP requests with a username keyword and commands and handles them as instructions to perform actions.[1]
Enterprise T1560 .003 Archive Collected Data: Archive via Custom Method

OwaAuth DES-encrypts captured credentials using the key 12345678 before writing the credentials to a log file.[1]
Enterprise T1083 File and Directory Discovery

OwaAuth has a command to list its directory and logical drives.[1]
Enterprise T1070 .006 Indicator Removal: Timestomp

OwaAuth has a command to timestop a file or directory.[1]
Enterprise T1056 .001 Input Capture: Keylogging

OwaAuth captures and DES-encrypts credentials before writing the username and password to a log file, C:\log.txt.[1]
Enterprise T1036 .005 Masquerading: Match Legitimate Name or Location

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 %ProgramFiles%\Microsoft\Exchange Server\ClientAccess\Owa\bin\.[1]
Enterprise T1505 .003 Server Software Component: Web Shell

OwaAuth is a Web shell that appears to be exclusively used by Threat Group-3390. It is installed as an ISAPI filter on Exchange servers and shares characteristics with the China Chopper Web shell.[1]
.004 Server Software Component: IIS Components

OwaAuth has been loaded onto Exchange servers and disguised as an ISAPI filter (owaauth.dll). The IIS w3wp.exe process then loads the malicious DLL.[1]

References

  1. Dell SecureWorks Counter Threat Unit Threat Intelligence. (2015, August 5). Threat Group-3390 Targets Organizations for Cyberespionage. Retrieved August 18, 2018.