Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 e1c0ec5104ddb005…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:40:55 Authoring application: Microsoft Excel First seen: 2021-10-01
MD5: fae52a6a29119a34560202cc4e20d001 SHA-1: 26dc79d4a30da886e2817ce2ccabbb037bae277a SHA-256: e1c0ec5104ddb005301e3d4ce567460c6d5c216593b6f4f2fa56b0e7af850d20
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 (XLM) macros with an Auto_Open entry, which is a common technique for executing malicious code upon opening the document. The macro sheet contains references to dangerous formula APIs, including RUN, suggesting it is designed to execute arbitrary commands. The presence of a large amount of obfuscated text in the document body further supports a malicious intent, likely to download and execute a second-stage 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) 6495 bytes
SHA-256: ba15d018caeeaca8e993f772c5c44422dd2b542a4fc17c66118b465dbfa41503
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     15 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  SpSvOS
' 0018     22 LABEL : Cell Value, String Constant - AaDJyAo len=0 
' 0018     21 LABEL : Cell Value, String Constant - ABxtUI len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!F136 
' 0018     27 LABEL : Cell Value, String Constant - bFmYgXSyDpMU len=0 
' 0018     25 LABEL : Cell Value, String Constant - bMjAUsDHoT len=0 
' 0018     26 LABEL : Cell Value, String Constant - CRmddLAfPqa len=0 
' 0018     27 LABEL : Cell Value, String Constant - DCZHugWBFomx len=0 
' 0018     21 LABEL : Cell Value, String Constant - ESFIWz len=0 
' 0018     21 LABEL : Cell Value, String Constant - GaxBip len=0 
' 0018     26 LABEL : Cell Value, String Constant - hZvesgkDsPd len=0 
' 0018     20 LABEL : Cell Value, String Constant - KiEoA len=0 
' 0018     27 LABEL : Cell Value, String Constant - KiQBRTCEtSqn len=0 
' 0018     23 LABEL : Cell Value, String Constant - OUpzEuxj len=0 
' 0018     27 LABEL : Cell Value, String Constant - QcRLTtTENHhT len=0 
' 0018     22 LABEL : Cell Value, String Constant - TfLgyyQ len=0 
' 0018     25 LABEL : Cell Value, String Constant - tLyBvPSemk len=0 
' 0018     26 LABEL : Cell Value, String Constant - VEAuGXwJiCV len=0 
' 0018     26 LABEL : Cell Value, String Constant - XKjdyUzOhyD len=0 
' 0018     25 LABEL : Cell Value, String Constant - YlRuBtGKyF len=0 
' 0018     22 LABEL : Cell Value, String Constant - yPAaWOX len=0 
' 0018     23 LABEL : Cell Value, String Constant - zocNgzlg 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/ SS
... (truncated)

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