Office (OOXML) / .XLSM malware analysis — malicious · cff18fed600a3731

MALICIOUS

Office (OOXML) / .XLSM

438.4 KB Created: 2021-07-28 10:37:27 UTC Authoring application: Microsoft Excel 12.0000

MD5: ebe0fb3b67cf38d3bdec7f62a08b50dd SHA-1: ab9150f74d09c686fdccafa2424d2a2d3cae1fca SHA-256: cff18fed600a3731c39199cb2ef0565f7c1499387a9f5a6be605e7f9f75e510b

148 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1059.003 Windows Command Shell

The sample is an XLSM file containing a Workbook_Open macro, indicating it's designed to execute code upon opening. The macro uses CreateObject to execute a command, constructing a path to a file named 'payload.exe' which is likely the second-stage payload. The Environ and Cells functions are used to dynamically construct the path and potentially the command to execute, suggesting an attempt to obfuscate the payload's location and name. The macro also writes data to a file, but its content is not directly discernible from the provided script.

Heuristics 5

Workbook_Open macro high OLE_VBA_WBOPEN

Workbook_Open macro
CreateObject call high OLE_VBA_CREATEOBJ

CreateObject call
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
Environ() call (env variable access) low OLE_VBA_ENVIRON

Environ() call (env variable access)

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas` `f82dcdf0d980a111e48d6b7e8bf0f569253aedffa510fc072db534d1f0e25795`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	1094 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` `a8190446c34a7cd3fa80f524a72f332a518366e3b88fd60d25ad5c64d5927d92`	vba-project	OOXML VBA project: xl/vbaProject.bin	9216 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved macro source contains an auto-exec entry point and execution/download terms.

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