Office (OLE) / .DOC malware analysis — malicious · f1a501d0f898794f

MALICIOUS

Office (OLE) / .DOC

258.5 KB Created: 2020-04-28 11:51:53 Authoring application: Microsoft Excel

MD5: d631d8d4f6f7459f1ee66d9ebb75c607 SHA-1: d50fea7b52c4ef5c06d2eacb6d13fc68a13cc7a5 SHA-256: f1a501d0f898794fd8c1c1a67124d6c1cb7b6b74c992baee9ed5da2ce78fd87d

260 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1204.002 Malicious File T1059.001 PowerShell T1105 Ingress Tool Transfer

The sample is an Excel 4.0 macro-enabled document. Heuristics indicate the presence of an Auto_Open macro that uses dangerous functions like RUN. The macro likely uses the URLDownloadToFile API to download and execute a second-stage payload, and ShellExecute to run it. The document body contains obfuscated text, suggesting an attempt to hide the malicious content.

Heuristics 6

Reference to URLDownloadToFile API critical SC_STR_URLDOWNLOAD

Reference to URLDownloadToFile API
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.
Reference to ShellExecute API high SC_STR_SHELLEXEC

Reference to ShellExecute API
OLE metadata lists many Excel 4.0 macro sheets medium OLE_XLM_DOCPROPS_MACROSHEET_INVENTORY

Workbook contains a BIFF Excel 4.0 macro-sheet marker and its clear OLE DocumentSummaryInformation stream lists many MacroN sheet titles. This is a useful static signal when FILEPASS encryption prevents formula extraction from the workbook stream.
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` `d6d4b0dc176cf590a36ef1a3c305a4592495e8dc768fa63d51c540ea0fa9f05a`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	42611 bytes

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