Office (OLE) / .DOC malware analysis — malicious · 8ae73acc01f72c11

MALICIOUS

Office (OLE) / .DOC

501.0 KB Created: 2021-12-03 17:38:00 Authoring application: Microsoft Office Word

MD5: 23f98d6ff7329618994ac0f3e2b3a394 SHA-1: 64ae82d4c4d66d2703e8e310e176808f380f727d SHA-256: 8ae73acc01f72c1164324e44045cd74256c3b4be606c0932717a2b593e8c5169

240 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File T1071.001 Web Protocols

The sample contains a VBA macro within an Auto_Close subroutine, which is designed to execute automatically when the document is closed. This macro attempts to reconstruct and write data to a file named '1.mstsc' in the 'C:\Users\Public\Documents\' directory. The use of `ShellExecute` and `CreateObject` API calls, along with the obfuscated writing of content to a file with a '.mstsc' extension (often associated with Remote Desktop Protocol, but here likely used to disguise an executable), strongly suggests the intent to download and execute a second-stage payload. The macro's obfuscation and the nature of the file writing operation indicate a downloader or droppper functionality.

Heuristics 7

Reference to ShellExecute API high SC_STR_SHELLEXEC

Reference to ShellExecute API
Auto_Close macro high OLE_VBA_AUTOCLOSE

Auto_Close macro
CreateObject call high OLE_VBA_CREATEOBJ

CreateObject call
GetObject call high OLE_VBA_GETOBJ

GetObject 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
Suspicious extracted artifact medium EXTRACTED_FILE_STATIC_TRIAGE

One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas` `a1fbd94b130c815122142e6237081acb5a45889600da0f6f7c6430d2c43c0c79`	vba-macro	oletools.olevba.extract_macros (decoded VBA source)	37204 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 shell/COM execution token(s).

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