Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 ac66a7ab259008ab…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:40:30 Authoring application: Microsoft Excel First seen: 2021-06-13
MD5: 3c0210105b03ec2f66a447b1d6ee649d SHA-1: 0007849b13f26b18482bc35fc2620d32870b52b1 SHA-256: ac66a7ab259008ab9b89240a4e296228efffa7c46ac01204f35d0d78f66e428e
140 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro-enabled workbook. Heuristics indicate the presence of an Auto_Open defined name and the use of dangerous formula APIs within the XLM macro sheet. This suggests the workbook is designed to automatically execute malicious code upon opening, 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) 6358 bytes
SHA-256: 55ecdef23be84a7e11175c1389bd58846286a447e7ebe27da696e9ee8613d906
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     12 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  OEJ
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!I187 
' 0018     21 LABEL : Cell Value, String Constant - cAXMrC len=0 
' 0018     21 LABEL : Cell Value, String Constant - cKaFIv len=0 
' 0018     22 LABEL : Cell Value, String Constant - cRcELYV len=0 
' 0018     23 LABEL : Cell Value, String Constant - DxRqtjVi len=0 
' 0018     21 LABEL : Cell Value, String Constant - ecVUsQ len=0 
' 0018     25 LABEL : Cell Value, String Constant - EdTBXkhLIE len=0 
' 0018     20 LABEL : Cell Value, String Constant - EpwKu len=0 
' 0018     20 LABEL : Cell Value, String Constant - gnyUS len=0 
' 0018     24 LABEL : Cell Value, String Constant - HjNShIhpD len=0 
' 0018     25 LABEL : Cell Value, String Constant - jiKOdnyFqn len=0 
' 0018     26 LABEL : Cell Value, String Constant - knZrDbAVvjC len=0 
' 0018     27 LABEL : Cell Value, String Constant - mdHxcgcutxeR len=0 
' 0018     23 LABEL : Cell Value, String Constant - MRLGTbzk len=0 
' 0018     25 LABEL : Cell Value, String Constant - nuWBskCvOC len=0 
' 0018     23 LABEL : Cell Value, String Constant - QVMitEyi len=0 
' 0018     27 LABEL : Cell Value, String Constant - RyrwWhhsxtwR len=0 
' 0018     22 LABEL : Cell Value, String Constant - SfsPyJL len=0 
' 0018     24 LABEL : Cell Value, String Constant - uriYvCIyC len=0 
' 0018     20 LABEL : Cell Value, String Constant - uSCNX len=0 
' 0018     24 LABEL : Cell Value, String Constant - vpOEahtmp 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 LABELS
... (truncated)

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