Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 31de67e357c1e336…

MALICIOUS

Office (OLE)

37.0 KB Created: 2020-11-27 11:40:07 Authoring application: Microsoft Excel First seen: 2021-11-02
MD5: e7ecb3b13041a54a7711f872f9ef69df SHA-1: 7344fd23218396716ffff58931b7c5f5cc92b33a SHA-256: 31de67e357c1e3368c33b2f058828f49b2de9003ead377d087dd44c2b99133a8
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open entry point, which is a common technique for executing malicious code upon opening the document. The macro sheet contains a call to a dangerous function, likely intended to download and execute a secondary payload. No specific family could be identified.

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) 6711 bytes
SHA-256: 019b9db0add2eb602e95e1bbe8ca46ff6ae6b46d00818fd7fc7adaeb1088456d
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     12 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  Nwq
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!I135 
' 0018     24 LABEL : Cell Value, String Constant - BclONjYvy len=0 
' 0018     23 LABEL : Cell Value, String Constant - BSXFtXJs len=0 
' 0018     27 LABEL : Cell Value, String Constant - clKpFYWZTtWQ len=0 
' 0018     27 LABEL : Cell Value, String Constant - DPtbsfjuvVaH len=0 
' 0018     27 LABEL : Cell Value, String Constant - DvdKgiIzLGkj len=0 
' 0018     26 LABEL : Cell Value, String Constant - EdqYATrzbnj len=0 
' 0018     23 LABEL : Cell Value, String Constant - gVUkpASt len=0 
' 0018     24 LABEL : Cell Value, String Constant - HadGMvUMH len=0 
' 0018     23 LABEL : Cell Value, String Constant - IccDajby len=0 
' 0018     27 LABEL : Cell Value, String Constant - IYvUQztBXuAZ len=0 
' 0018     25 LABEL : Cell Value, String Constant - jzLrmYKiGB len=0 
' 0018     27 LABEL : Cell Value, String Constant - MEtXfnovZKKc len=0 
' 0018     23 LABEL : Cell Value, String Constant - NBdFiyRM len=0 
' 0018     25 LABEL : Cell Value, String Constant - nMJsRfhfmD len=0 
' 0018     20 LABEL : Cell Value, String Constant - PTAmV len=0 
' 0018     27 LABEL : Cell Value, String Constant - RuNWAMTdDklw len=0 
' 0018     24 LABEL : Cell Value, String Constant - SChNnSRwT len=0 
' 0018     21 LABEL : Cell Value, String Constant - usSEcj len=0 
' 0018     22 LABEL : Cell Value, String Constant - UZaQHOb len=0 
' 0018     24 LABEL : Cell Value, String Constant - xUIkOxUje 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
... (truncated)

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