Malicious Office (OLE) / .XLSX — malware analysis report

Static analysis result for SHA-256 90817107cedcf188…

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-27 11:47:41 Authoring application: Microsoft Excel
MD5: 2277e249235b1763a5a12e9368cea135 SHA-1: 63fb4eca1040ea1aae885d3f4d043dcd48536adc SHA-256: 90817107cedcf1882eaca675881ee0f9db30f0ad22faf04804336378bc77f32a
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1059.003 Windows Command Shell

The file contains Excel 4.0 (XLM) macro sheets, specifically triggering an Auto_Open function. This function is known to be used for executing arbitrary commands, often to download and run a second-stage payload. The presence of 'risky-formula=2; RUN=0' in the heuristics indicates the use of dangerous functions within the macro, further supporting the execution of external commands. No specific URLs or hashes were extracted, but the Auto_Open macro itself is a critical indicator of malicious intent.

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
74c38b7f4e3459334d7dad320f8e9efbe1bd85613b0276ef98bde4efae84351b		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6814 bytes
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     18 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  cKZBzVYOe
' 0018     22 LABEL : Cell Value, String Constant - alIuOEr len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!F129 
' 0018     20 LABEL : Cell Value, String Constant - CQryO len=0 
' 0018     22 LABEL : Cell Value, String Constant - dkXvfTc len=0 
' 0018     26 LABEL : Cell Value, String Constant - fEkhWWgPntq len=0 
' 0018     27 LABEL : Cell Value, String Constant - fICqyWdcfRTN len=0 
' 0018     25 LABEL : Cell Value, String Constant - IZHRyZtOyN len=0 
' 0018     22 LABEL : Cell Value, String Constant - lCOlKYN len=0 
' 0018     27 LABEL : Cell Value, String Constant - MoyFqaBveEVq len=0 
' 0018     21 LABEL : Cell Value, String Constant - MxCFsg len=0 
' 0018     23 LABEL : Cell Value, String Constant - nLcrCYsD len=0 
' 0018     21 LABEL : Cell Value, String Constant - oxQsMP len=0 
' 0018     21 LABEL : Cell Value, String Constant - pyBISr len=0 
' 0018     23 LABEL : Cell Value, String Constant - pzqyAmAd len=0 
' 0018     21 LABEL : Cell Value, String Constant - qSRqDh len=0 
' 0018     21 LABEL : Cell Value, String Constant - RSaDrj len=0 
' 0018     21 LABEL : Cell Value, String Constant - ubndrz len=0 
' 0018     23 LABEL : Cell Value, String Constant - vaemHMqC len=0 
' 0018     20 LABEL : Cell Value, String Constant - XvFJU len=0 
' 0018     25 LABEL : Cell Value, String Constant - YkdiOmgLKo len=0 
' 0018     27 LABEL : Cell Value, String Constant - ZmsVMiLEXkUy 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 LABEL
... (truncated)

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