Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 e85de3ae7dc777e3…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:42:17 Authoring application: Microsoft Excel First seen: 2021-09-22
MD5: 0249e25f1f9e8744240531083c1d04a3 SHA-1: 235aaf418a1f5a45def643d709059c9a1b43879a SHA-256: e85de3ae7dc777e3dee3a797940604589bbbac288929a67f174a691a961a76b9
140 Risk Score

Malware Insights

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

The sample is an Excel 4.0 macro-enabled workbook. Heuristics indicate the presence of an Auto_Open macro and the use of dangerous formula APIs, specifically the RUN function. This suggests the macro is designed to execute arbitrary code, likely a second-stage payload, upon opening the document.

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) 6862 bytes
SHA-256: 51c653dd9abc773394a4e95cfe131aa0662bdf00be6cda6705cad60649d7ee7e
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 -  AzXpjzEn
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C159 
' 0018     26 LABEL : Cell Value, String Constant - dQxSDkUNKIN len=0 
' 0018     21 LABEL : Cell Value, String Constant - feCVbY len=0 
' 0018     24 LABEL : Cell Value, String Constant - FvxxGZswR len=0 
' 0018     25 LABEL : Cell Value, String Constant - htBGxldqEr len=0 
' 0018     26 LABEL : Cell Value, String Constant - ixMxziKyinq len=0 
' 0018     20 LABEL : Cell Value, String Constant - jRLbt len=0 
' 0018     26 LABEL : Cell Value, String Constant - kEpblqOlIma len=0 
' 0018     24 LABEL : Cell Value, String Constant - KXbyrslxU len=0 
' 0018     23 LABEL : Cell Value, String Constant - LPsfRKgT len=0 
' 0018     22 LABEL : Cell Value, String Constant - MdIIPYh len=0 
' 0018     26 LABEL : Cell Value, String Constant - NVLdwQSwslZ len=0 
' 0018     20 LABEL : Cell Value, String Constant - oKmYw len=0 
' 0018     26 LABEL : Cell Value, String Constant - QVRHzBuSMpM len=0 
' 0018     24 LABEL : Cell Value, String Constant - SeuKcwKIM len=0 
' 0018     23 LABEL : Cell Value, String Constant - siyRTtTE len=0 
' 0018     26 LABEL : Cell Value, String Constant - TYRTvrpIGPo len=0 
' 0018     21 LABEL : Cell Value, String Constant - UVMKsk len=0 
' 0018     27 LABEL : Cell Value, String Constant - VQvnHrCONIxS len=0 
' 0018     24 LABEL : Cell Value, String Constant - vsCxVswiY len=0 
' 0018     22 LABEL : Cell Value, String Constant - zkaFVwJ 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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