Office (OOXML) / .XLSM malware analysis — malicious · 3a5943219f840053

MALICIOUS

Office (OOXML) / .XLSM

93.8 KB Created: 2020-05-19 19:55:29 UTC Authoring application: Microsoft Excel 12.0000

MD5: 69e4dd490a6b0fd7740dd7eb3a0020e2 SHA-1: 51ef9cb92805c807f4b7effe25a4171c310ae8ae SHA-256: 3a5943219f8400531a411b909b666337ba4f232d19e003a0128e0d699106f04f

220 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1059 Command and Scripting Interpreter

The file is an XLSM document containing VBA macros. A Workbook_Open macro is present, which is designed to execute automatically when the document is opened. This macro utilizes a character-shift decoder to obfuscate a Shell() command, indicating an attempt to download and execute a second-stage payload. The presence of a Workbook_Open macro and the use of Shell() are strong indicators of malicious intent.

Heuristics 5

Shell() call in VBA critical OLE_VBA_SHELL

Shell() call in VBA
VBA character-shift decoded Shell command critical OLE_VBA_ASC_CHR_SHIFT_SHELL

VBA auto-exec macro stores an encoded command string, decodes it with a Mid/Asc/Chr character-shift loop, and passes the recovered text to Shell. This is a high-confidence command stager.
Workbook_Open macro high OLE_VBA_WBOPEN

Workbook_Open macro
Suspicious extracted artifact high 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.
VBA project inside OOXML medium OOXML_VBA

Document contains vbaProject.bin — VBA macros present

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas` `5317002e107a763c824c199f319d0b409a142f3fd9350d8f909246ab62c52735`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	1622 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved macro source contains an auto-exec entry point and execution/download terms.
`vbaProject_00.bin` `262e135265c0f7b9c1f9ded7725b4deceea0e459c944778315197c2f4dbd144b`	vba-project	OOXML VBA project: xl/vbaProject.bin	13312 bytes

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