Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 19661040d261b1e1…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:40:21 Authoring application: Microsoft Excel First seen: 2021-07-02
MD5: 911de34ae8828814c46aa62a84e658a1 SHA-1: 6f3e6ab1794e5126efbcd6a712ee39e32ba635b6 SHA-256: 19661040d261b1e1152db69dd81f5a37904e9e75430f10e1775784fd0d0c7cbc
140 Risk Score

Malware Insights

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

The sample is an Excel file containing Excel 4.0 (XLM) macros, specifically triggering an Auto_Open function. This indicates the file is designed to automatically execute code upon opening. The presence of dangerous formula APIs like RUN suggests the macro is intended to download and execute a secondary payload, a common technique for initial access and further compromise.

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) 6445 bytes
SHA-256: 227fc410167a6b48aa3c8622ebe5a88224bb843e8556db8ff8ecc44c2ee8344b
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     16 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  mTVqQdJ
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A178 
' 0018     23 LABEL : Cell Value, String Constant - BznZDRBM len=0 
' 0018     21 LABEL : Cell Value, String Constant - cAvHhg len=0 
' 0018     21 LABEL : Cell Value, String Constant - cxnAXL len=0 
' 0018     22 LABEL : Cell Value, String Constant - EKNEitv len=0 
' 0018     20 LABEL : Cell Value, String Constant - FajZt len=0 
' 0018     25 LABEL : Cell Value, String Constant - FQycKdoAfl len=0 
' 0018     20 LABEL : Cell Value, String Constant - FuaOH len=0 
' 0018     21 LABEL : Cell Value, String Constant - hFyowY len=0 
' 0018     21 LABEL : Cell Value, String Constant - kpvpMt len=0 
' 0018     23 LABEL : Cell Value, String Constant - LNHRLCsk len=0 
' 0018     21 LABEL : Cell Value, String Constant - lQFQgu len=0 
' 0018     21 LABEL : Cell Value, String Constant - LsZgaV len=0 
' 0018     26 LABEL : Cell Value, String Constant - NEZVnCMnLkt len=0 
' 0018     23 LABEL : Cell Value, String Constant - qrdwmNjp len=0 
' 0018     24 LABEL : Cell Value, String Constant - tsnkGQPzt len=0 
' 0018     24 LABEL : Cell Value, String Constant - vJRHnKNoi len=0 
' 0018     23 LABEL : Cell Value, String Constant - VSbQBDRx len=0 
' 0018     27 LABEL : Cell Value, String Constant - wMRFjTJqnEdn len=0 
' 0018     20 LABEL : Cell Value, String Constant - YrmPD len=0 
' 0018     20 LABEL : Cell Value, String Constant - znwPr 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
' 00fd     10 LABELSST : Cell Val
... (truncated)