Office (OLE) / .XLS malware analysis — malicious · ef0bc2e5622cc604

MALICIOUS

Office (OLE) / .XLS

36.0 KB Created: 2020-11-27 11:46:38 Authoring application: Microsoft Excel First seen: 2022-04-19

MD5: dd41a0dcb85722aa0ededf12eb69e30e SHA-1: bae5a632dae89af9b76dadc00827ef6842f94cc3 SHA-256: ef0bc2e5622cc604cf3e9ab4f2341b1976f74e8a5685e156fb9f69bc498302f0

140 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic

The sample is an Excel 4.0 macro-enabled spreadsheet. Heuristics indicate the presence of an Auto_Open macro and the use of dangerous functions like RUN, suggesting it's designed to execute arbitrary code upon opening. The macro sheet itself contains numerous string constants, but the specific commands or URLs they form are truncated in the provided evidence, preventing a more detailed analysis of the 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` `da5c0e1ecf46caaa1dae6ccf2e9371252387cfd21a0c754d6868f038a49eb2c9`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	6525 bytes

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