Office (OLE) / .XLSX malware analysis — malicious · 96901ccc03a5560c

MALICIOUS

Office (OLE) / .XLSX

36.5 KB Created: 2020-11-25 10:39:59 Authoring application: Microsoft Excel

MD5: 4534a1bd9d6a3b8a9fde59bbad32a1d1 SHA-1: 466bbbe77776799ce4adb13eccc0e4e2d8fa96c8 SHA-256: 96901ccc03a5560ced03098a90279b1ce3d36fd931bd7a68f452fb511cd61924

140 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1059.001 PowerShell

The sample contains an Excel 4.0 macro sheet with an Auto_Open defined name, which is a known technique for executing malicious code upon opening the workbook. The critical heuristic firings indicate the presence of dangerous formula APIs, specifically the RUN function, suggesting the macro is designed to execute arbitrary commands. No specific URLs or hashes were extracted, but the Auto_Open technique is a high-priority indicator.

Heuristics 3

Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME

oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN

Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN

Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_macros.txt` `afd15eaf229ba1c1bf6c24d2f285420efb84af7a60f3a73272f3040c4d057439`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	6642 bytes

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