Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b660e66a88f46ddc…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-25 10:38:53 Authoring application: Microsoft Excel First seen: 2021-09-15
MD5: 64a35e051462f4c02ca4658524661321 SHA-1: 725932ea65af6c32a29f3f6c00ef7d98cb67c106 SHA-256: b660e66a88f46ddc8f4f4d08060b1010411d31fba13a665e405fcb90f503bb03
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 containing an Auto_Open function. This function is designed to execute arbitrary code upon opening, as indicated by the critical heuristic firings for dangerous formula APIs. The macro sheet itself contains obfuscated data, suggesting an attempt to hide its 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 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6522 bytes
SHA-256: a08aeb0a6f119631eeab523516dfaf4cb278e271a9b63b3a55086a3769ed0d3b
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 -  RNUVDs
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E140 
' 0018     20 LABEL : Cell Value, String Constant - beriv len=0 
' 0018     24 LABEL : Cell Value, String Constant - BZLBpaOaJ len=0 
' 0018     20 LABEL : Cell Value, String Constant - CjOrx len=0 
' 0018     23 LABEL : Cell Value, String Constant - GRorqSED len=0 
' 0018     23 LABEL : Cell Value, String Constant - hIrmoENP len=0 
' 0018     23 LABEL : Cell Value, String Constant - hJCGdJsS len=0 
' 0018     21 LABEL : Cell Value, String Constant - jdPVvx len=0 
' 0018     27 LABEL : Cell Value, String Constant - JWsZYbnLHKZX len=0 
' 0018     25 LABEL : Cell Value, String Constant - kFDHoxMwvD len=0 
' 0018     20 LABEL : Cell Value, String Constant - KSOuu len=0 
' 0018     21 LABEL : Cell Value, String Constant - ktOVpZ len=0 
' 0018     20 LABEL : Cell Value, String Constant - lCgRH len=0 
' 0018     24 LABEL : Cell Value, String Constant - nbZLDRVby len=0 
' 0018     20 LABEL : Cell Value, String Constant - nglrK len=0 
' 0018     21 LABEL : Cell Value, String Constant - omReQO len=0 
' 0018     26 LABEL : Cell Value, String Constant - pBiZAhEPKca len=0 
' 0018     21 LABEL : Cell Value, String Constant - TIKXKZ len=0 
' 0018     27 LABEL : Cell Value, String Constant - TleXrFOEcLfs len=0 
' 0018     25 LABEL : Cell Value, String Constant - wtxjcPgLnc len=0 
' 0018     23 LABEL : Cell Value, String Constant - yQJprIUf 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 LABELSST : C
... (truncated)

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