Office (OLE) malware analysis — malicious · 19cafd0b04e0aa40

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-25 10:42:25 Authoring application: Microsoft Excel

MD5: 97070b5e0818a166c82cd9de1f86d054 SHA-1: f8cc2f49fa676f2e64a8c3487071ae3a160685db SHA-256: 19cafd0b04e0aa4079822fea94dedcbca007dcd18615c49e964b93e8040290dd

140 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1203 Exploitation for Client Execution

This Excel file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a known technique for executing malicious code upon opening the workbook. The critical heuristics indicate the presence of dangerous formula APIs within the Auto_Open macro, suggesting it's designed to run arbitrary commands. The macro likely functions as a downloader for a second-stage payload, although no specific URLs or hashes were extracted from this file.

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` `97b3239d8134e1c7b9ca1fa89de6ca3783eef534d2e814e7a0b092f35552f1bb`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	6434 bytes

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