Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 6c7e183c2257b4e1…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:43:24 Authoring application: Microsoft Excel First seen: 2021-09-29
MD5: fbe2f6414ad1f60b5d20434905179240 SHA-1: 032bd9d7d06c4e5e9765c5d21133a2683c376066 SHA-256: 6c7e183c2257b4e1e7e2fa7b5dedd7866d02e2a553f0acb3b3b0fe90e8944ab8
140 Risk Score

Malware Insights

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

This Excel file contains Excel 4.0 macros, specifically an Auto_Open function, which is a known technique for executing malicious code upon opening. The critical heuristics indicate the presence of dangerous formula APIs within the Auto_Open macro, suggesting it's designed to run arbitrary commands. The macro sheet itself contains obfuscated strings and references, typical of malware attempting to hide its 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.

FilenameKindSourceSize
xlm_macros.txt xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6778 bytes
SHA-256: e0f23a062bdda102a112a538cdca28abe220850a2f5f7636bf7363ed146198b9
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     17 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  pMeNDCAE
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E159 
' 0018     25 LABEL : Cell Value, String Constant - CifbQaAEPz len=0 
' 0018     27 LABEL : Cell Value, String Constant - GLXAZSAQrjLY len=0 
' 0018     24 LABEL : Cell Value, String Constant - hAPoQqKEn len=0 
' 0018     27 LABEL : Cell Value, String Constant - IEDiUvKqggFA len=0 
' 0018     27 LABEL : Cell Value, String Constant - kQVTAAOdibxB len=0 
' 0018     25 LABEL : Cell Value, String Constant - LjMmPUwtIN len=0 
' 0018     20 LABEL : Cell Value, String Constant - lYbzn len=0 
' 0018     25 LABEL : Cell Value, String Constant - mUwHjeWlnw len=0 
' 0018     21 LABEL : Cell Value, String Constant - MZRaFq len=0 
' 0018     25 LABEL : Cell Value, String Constant - ngIhMEsnhG len=0 
' 0018     24 LABEL : Cell Value, String Constant - nwgCWFHTq len=0 
' 0018     21 LABEL : Cell Value, String Constant - OpwKWz len=0 
' 0018     24 LABEL : Cell Value, String Constant - RmBDMrJVO len=0 
' 0018     21 LABEL : Cell Value, String Constant - TOQlkV len=0 
' 0018     26 LABEL : Cell Value, String Constant - usxJqHKEWGe len=0 
' 0018     27 LABEL : Cell Value, String Constant - wgelRBlCMfTJ len=0 
' 0018     21 LABEL : Cell Value, String Constant - XAbMxY len=0 
' 0018     22 LABEL : Cell Value, String Constant - XnrPccX len=0 
' 0018     27 LABEL : Cell Value, String Constant - YTmGiYUIBJOU len=0 
' 0018     20 LABEL : Cell Value, String Constant - yTOyg len=0 
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
... (truncated)

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