Office (OOXML) / .XLSX malware analysis — malicious · 1242e07f0cdfe9f7

MALICIOUS

Office (OOXML) / .XLSX

20.0 KB Created: 2021-08-09 09:06:15 UTC Authoring application: Microsoft Excel 15.0300

MD5: fe7b200f4c8438112be58ccf0a80dad5 SHA-1: 2e4fe02f192098a42963c8b56ef2c3566dc4f2f9 SHA-256: 1242e07f0cdfe9f71f9e871c5cac57f24b2c4db3ff1fc36c2181d23b7f6c368f

322 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1204.002 Malicious File

The XLSX file contains a Workbook_Open macro that triggers obfuscated VBA code. This code utilizes WScript.Shell and CreateObject to likely download and execute a second-stage payload, indicated by the 'Obfuscated auto-exec VBA loader' heuristic. The VBA code appears to be attempting to construct a command or URL, but it is heavily truncated and obfuscated, preventing full reconstruction.

Heuristics 8

Shell() call in VBA critical OLE_VBA_SHELL

Shell() call in VBA
WScript.Shell usage critical OLE_VBA_WSCRIPT

WScript.Shell usage
Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER

Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
Workbook_Open macro high OLE_VBA_WBOPEN

Workbook_Open macro
CreateObject call high OLE_VBA_CREATEOBJ

CreateObject 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 project inside OOXML medium OOXML_VBA

Document contains a VBA project — VBA macros present
Suspicious extracted artifact info 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 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas` `05b21a0b9b328173782d1a36b6a315256dd62bc1950d8291c7ccd6adeccc2eb0`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	9224 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 8 long base64-like blob(s).
`vbaProject_00.bin` `10b31b1fdfe4ca9b9572bac30acb4157f16023db10e7be2f774d69c7e4a19de4`	vba-project	OOXML VBA project: xl/vbaProject.bin	29696 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 8 long base64-like blob(s).

Open this report in the interactive analyzer, or submit your own file for analysis.