Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 5ad7d87fb527878c…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-25 10:44:31 Authoring application: Microsoft Excel First seen: 2021-06-13
MD5: 34b9b0a51c20d8ad66adee718744efdd SHA-1: db4f34779a4d2bc8b0f1275c65252d9b0b2d5b93 SHA-256: 5ad7d87fb527878cc55f46e2b74b0f8c322ba69dce8b70c66f2b236158007183
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, which is a known technique for executing malicious code. The macro sheet contains a reference to 'Auto_Open' and uses dangerous formula APIs, specifically 'RUN'. This strongly suggests the macro is designed to download and execute a secondary 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) 6642 bytes
SHA-256: 1167c0bf5fef4a6d8119a75e32e0c77ac0fa5439792477ebdf201a653798ffb5
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     20 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  wFHOHAvKTyI
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C146 
' 0018     21 LABEL : Cell Value, String Constant - AXoEEv len=0 
' 0018     27 LABEL : Cell Value, String Constant - BCGTCtMHBXWr len=0 
' 0018     23 LABEL : Cell Value, String Constant - fONqwJmW len=0 
' 0018     27 LABEL : Cell Value, String Constant - FXXyDdfDzzRN len=0 
' 0018     21 LABEL : Cell Value, String Constant - hcwOiP len=0 
' 0018     20 LABEL : Cell Value, String Constant - LudzC len=0 
' 0018     20 LABEL : Cell Value, String Constant - maPwp len=0 
' 0018     20 LABEL : Cell Value, String Constant - MAWCh len=0 
' 0018     23 LABEL : Cell Value, String Constant - MbWnNHhu len=0 
' 0018     24 LABEL : Cell Value, String Constant - NBbqTGPET len=0 
' 0018     21 LABEL : Cell Value, String Constant - PHMhUU len=0 
' 0018     21 LABEL : Cell Value, String Constant - QaFeMj len=0 
' 0018     25 LABEL : Cell Value, String Constant - QnxEhqPWtU len=0 
' 0018     26 LABEL : Cell Value, String Constant - RbsGyOKaGwn len=0 
' 0018     26 LABEL : Cell Value, String Constant - RQNJbwtXuuz len=0 
' 0018     22 LABEL : Cell Value, String Constant - uULJSfh len=0 
' 0018     21 LABEL : Cell Value, String Constant - VQsbUO len=0 
' 0018     21 LABEL : Cell Value, String Constant - WLycnX len=0 
' 0018     24 LABEL : Cell Value, String Constant - XnKwDPwGu len=0 
' 0018     21 LABEL : Cell Value, String Constant - ZdRFWr 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 LABELSS
... (truncated)

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