Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 90f78c81901031dd…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-25 10:39:58 Authoring application: Microsoft Excel First seen: 2021-10-14
MD5: ccef9a717483d48dd5b51b93d916e8d1 SHA-1: f972fe6d5f716ed5aa8bccd68dcdb6ddb676a73b SHA-256: 90f78c81901031ddc5bdae2c70f9c95f13ca369d816a9825e38c3901f4d3d599
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 (XLM) macros, specifically an Auto_Open defined name, which is a critical finding indicating automatic execution upon opening. The presence of dangerous formula APIs like RUN further suggests the macro is designed to execute arbitrary commands. No specific family could be identified, but the technique is consistent with macro-based malware.

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) 6562 bytes
SHA-256: 4b042aa5b6290e19a40aba726757bba8c6ba64373f479e5c956232091ab33d91
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 -  FgrEcC
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!D153 
' 0018     23 LABEL : Cell Value, String Constant - aXyWtOax len=0 
' 0018     22 LABEL : Cell Value, String Constant - BvSicch len=0 
' 0018     25 LABEL : Cell Value, String Constant - FKJXvQrHvH len=0 
' 0018     27 LABEL : Cell Value, String Constant - GWsPKOSZTGqJ len=0 
' 0018     21 LABEL : Cell Value, String Constant - hrfVeu len=0 
' 0018     27 LABEL : Cell Value, String Constant - IhhKVUIrdvpS len=0 
' 0018     24 LABEL : Cell Value, String Constant - IiERmnFfk len=0 
' 0018     22 LABEL : Cell Value, String Constant - ITpBgOI len=0 
' 0018     24 LABEL : Cell Value, String Constant - jRmQLvqmJ len=0 
' 0018     20 LABEL : Cell Value, String Constant - lxdbM len=0 
' 0018     22 LABEL : Cell Value, String Constant - PAcHNMB len=0 
' 0018     24 LABEL : Cell Value, String Constant - QeemRFbdQ len=0 
' 0018     23 LABEL : Cell Value, String Constant - QIMcioxT len=0 
' 0018     22 LABEL : Cell Value, String Constant - RpLBqOY len=0 
' 0018     27 LABEL : Cell Value, String Constant - TGxWnRpmoLEl len=0 
' 0018     25 LABEL : Cell Value, String Constant - TldjTqGrXj len=0 
' 0018     27 LABEL : Cell Value, String Constant - VepPiaNyGiyz len=0 
' 0018     23 LABEL : Cell Value, String Constant - wjPRLpxD len=0 
' 0018     24 LABEL : Cell Value, String Constant - zMWUolfZC len=0 
' 0018     24 LABEL : Cell Value, String Constant - ZzAGMTrRo 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
' 00
... (truncated)

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