Office (OLE) / .XLS malware analysis — malicious · 69ab644fb35bff52

MALICIOUS

Office (OLE) / .XLS

41.5 KB Created: 2020-09-28 00:53:43 Authoring application: Microsoft Excel

MD5: a25f16b71feac96810800c7d281a93d8 SHA-1: e5d716e4d3687e79e99a70607bcbcec37ebfa73d SHA-256: 69ab644fb35bff52b9fb5b4d8cff404ea4269d01a0dc34ab7bac1fd9e353ef09

140 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1203 Exploitation for Client Execution

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open function, which is a known method for executing malicious code. The macro sheet contains a reference to 'Auto_Open', suggesting it will run automatically when the workbook is opened. The presence of dangerous formula APIs like RUN further confirms its malicious intent, likely to download and execute a secondary payload.

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` `fb962d37c70b6549fd5125fcc33822237358b0cc6bf1636fa73de498a5bf4a29`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	8143 bytes

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