Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c5c4f08431b453c0…

MALICIOUS

Office (OLE)

238.0 KB Created: 2021-07-23 18:34:00 Authoring application: Microsoft Office Word
MD5: d76972e44f354169a094f361973767fc SHA-1: ec22e831f7395d071dc480819787dbf64a082c15 SHA-256: c5c4f08431b453c03ebf5516e4c5ef0265dfbc68b3a2ea6b2c91861d96891ee5
280 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1218.011 System Binary Proxy Execution: Rundll32 T1059 Command and Scripting Interpreter

The sample contains VBA macros that are triggered by the Document_Open event. These macros utilize the GetObject function to instantiate the dangerous COM class 'Shell.Application' (CLSID {13709620-C279-11CE-A49E-444553540000}). The script then uses the ShellExecute method of this object to execute a command, likely a second-stage payload, based on the value of the 'Comments' document property. This indicates a macro-based execution chain designed to download and run further malicious content.

Heuristics 7

  • VBA instantiates a dangerous COM class by CLSID critical OLE_VBA_GETOBJECT_CLSID_DANGEROUS
    VBA uses GetObject("new:{CLSID}") to instantiate an execution/scripting-capable COM class by its raw CLSID, avoiding the CreateObject ProgID that name-based detection keys on.
  • Reference to ShellExecute API high SC_STR_SHELLEXEC
    Reference to ShellExecute API
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
  • CallByName call high OLE_VBA_CALLBYNAME
    CallByName call
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • VBA macros detected medium OLE_VBA_MACROS
    Document contains VBA macro code

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
c8d5435da7c4c8850ea23b3649733fe7d6596d8db07e78c3dd69ff9406b761b8		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 1178 bytes

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