Office (OLE) / .XLS malware analysis — malicious · efb66a70d2ef394a

MALICIOUS

Office (OLE) / .XLS

71.0 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-06-07

MD5: 7d8f85c1d69954a3bc59db6f0d12a20a SHA-1: 862794b52e76753b3c301edca5bab305b325e1bb SHA-256: efb66a70d2ef394ae7b10e204d50f6ebd6a92ce5e353cf6cda359230e380048a

140 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic for Applications T1204.002 Malicious File

The critical OLE_XLM_AUTOOPEN_DEFINEDNAME and OLE_XLM_DANGEROUS_FN heuristics indicate the presence of an Excel 4.0 Auto_Open macro that calls dangerous functions like RUN. The extracted URLs are likely used to download and execute a second-stage payload. The macro itself is heavily truncated, but the presence of the Auto_Open function and the RUN API call strongly suggests malicious intent.

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` `5111faade6798439ce43161a25c95a0c795073df8f05008e90c40cef2fd124d6`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	7798 bytes

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