Malicious Office (OLE) / .XLS — malware analysis report

Static analysis result for SHA-256 5aa82085d0e21dfe…

MALICIOUS

Office (OLE) / .XLS

70.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-06-03
MD5: 5c493563c7c87cb96eee7077a179b2cf SHA-1: f48e583f542d64e0930bd6011d7a7ca63bd2434a SHA-256: 5aa82085d0e21dfe6198f58076142c8e80e253b8575ab2723918bb4a9915cd79
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open entry, which is a known technique for executing malicious code upon opening the document. The extracted URLs suggest the macro is designed to download a second-stage payload. The use of Auto_Open with dangerous functions points to an intentional malicious execution flow.

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.

FilenameKindSourceSize
xlm_macros.txt
b2124f09a0fec7faeef42f88c68da164b6a9b84efed16f528c7ac11c7695b4b9		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7646 bytes

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