Office (OLE) / .XLS malware analysis — malicious · 4947b0fd4d2972fc

MALICIOUS

Office (OLE) / .XLS

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

MD5: 3b45c3a17f6f85b1bdf017cb17a0df9c SHA-1: 7639a442d28f141e26c093f12630a63b4c5c3dc9 SHA-256: 4947b0fd4d2972fc10c4e5eb6ba54105d870af146c0dd45190f5bba648b6c113

140 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Service Execution: Visual Basic T1204.002 Malicious File: Malicious File

The critical heuristics OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN indicate the presence of an Excel 4.0 macro sheet with an Auto_Open function that uses the RUN API. The extracted URLs suggest the macro is intended to download and execute a second-stage payload. The macro sheet itself contains references to these URLs, confirming their role in the attack chain.

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` `f83c1e7392699acb02f69ec3ffd4b4b11e29d3a6381df4b6ea4e60977f47b16d`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	7590 bytes

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