Office (OOXML) / .XLSM malware analysis — suspicious · 71fb5ec5a1424b99

SUSPICIOUS

Office (OOXML) / .XLSM

329.3 KB Created: 2021-07-26 11:42:26 UTC Authoring application: Microsoft Excel 12.0000

MD5: 6cb632b4c2e9244c36ad740ef8cbfda5 SHA-1: 5c90034815dc6faf9d14da1536f05a8a9a1d0f73 SHA-256: 71fb5ec5a1424b9965bf487a41e24e04e6cd20fb256b283b8262a6592aa90114

40 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1059 Command and Scripting Interpreter T1204.002 Malicious File

The sample is an XLSM file containing a Workbook_Open macro that executes code via the Shell() function. The macro constructs a path to a temporary file and then attempts to execute it. This indicates a downloader or dropper functionality, aiming to execute a second-stage payload.

Heuristics 6

Shell() call in VBA critical OLE_VBA_SHELL

Shell() call in VBA
Workbook_Open macro high OLE_VBA_WBOPEN

Workbook_Open macro
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 project inside OOXML medium OOXML_VBA

Document contains a VBA project — VBA macros present
Environ() call (env variable access) low OLE_VBA_ENVIRON

Environ() call (env variable access)
Macro capabilities present but unconfirmed info MACRO_CAPABILITY_UNCORROBORATED

The document's VBA exposes execution capabilities (Shell/WScript/CreateObject/auto-exec) but nothing corroborates malicious intent — no obfuscation, memory-exec primitive, download+exec chain, encoded payload, LOLBin, DDE, AV hit, or suspicious URL. The verdict was capped at 'suspicious' so legitimate macro-heavy business documents are not flagged malicious on capability presence alone.

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas` `86b8b9e48cdcd034cbe1fa1e39d930a55bd99c624d4fa8b410fcfb105fcb3d70`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	1030 bytes
`vbaProject_00.bin` `d98176cf98ba37eee42c35b169274dc5a8b30b7f7bb648f5f5771f4a1cebb4c4`	vba-project	OOXML VBA project: xl/vbaProject.bin	9216 bytes

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