Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 aca489f0fc895526…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:38:46 Authoring application: Microsoft Excel
MD5: ac03a2d9b008d75a4d5781ba90d6ab75 SHA-1: 043f1af8805ea0cb21c958d1535b87a3fb195c0a SHA-256: aca489f0fc8955260e4fb24aacc59a261891fd40e0fbcfcc3be9cc651b8035eb
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical indicator of malicious intent. This technique is often used to deliver secondary payloads or perform malicious actions upon opening the document. The presence of the Auto_Open function and the use of dangerous formula APIs strongly suggest an attempt to execute arbitrary code, likely delivered via spearphishing.

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
75e87b124eb1c22f296a88122a687e95d122895f8fcc470c48b7dc7d4c78d807		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6689 bytes

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