Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 4a811fb8690e164d…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:42:24 Authoring application: Microsoft Excel First seen: 2021-06-13
MD5: cdc661f680fb4db9300f386d5792bdf3 SHA-1: 17ad0dd1474bd8e0b933ae07a1dc1b16d9f3781c SHA-256: 4a811fb8690e164d5c39e867f722100708ca42844b4b0ee221798a143f2e6e27
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 function, which is a common method for executing malicious code upon opening the document. The macro sheet contains formulas that are flagged as dangerous, suggesting it attempts to run arbitrary commands. The presence of an Auto_Open entry points to an attempt to execute a payload, likely a downloader.

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) 6658 bytes
SHA-256: 67b47ad5ee7668b85ecc8bc8008f545c1841b2f56d2b247462db454bf291bd9a
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     14 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  sjbon
' 0018     24 LABEL : Cell Value, String Constant - AJpszKdgZ len=0 
' 0018     25 LABEL : Cell Value, String Constant - ANhDNCAlkf len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!G176 
' 0018     27 LABEL : Cell Value, String Constant - eISWaRLKofoi len=0 
' 0018     20 LABEL : Cell Value, String Constant - FAACx len=0 
' 0018     26 LABEL : Cell Value, String Constant - foHfNbYBuez len=0 
' 0018     21 LABEL : Cell Value, String Constant - gJUvCF len=0 
' 0018     21 LABEL : Cell Value, String Constant - HQDcJQ len=0 
' 0018     20 LABEL : Cell Value, String Constant - hzZya len=0 
' 0018     27 LABEL : Cell Value, String Constant - IBrIpUwhwjUU len=0 
' 0018     24 LABEL : Cell Value, String Constant - IVZmTtfye len=0 
' 0018     25 LABEL : Cell Value, String Constant - JjALHfnCpO len=0 
' 0018     23 LABEL : Cell Value, String Constant - kdowuHJa len=0 
' 0018     25 LABEL : Cell Value, String Constant - LHwVJDMJLs len=0 
' 0018     27 LABEL : Cell Value, String Constant - mWifzmfpzkKo len=0 
' 0018     22 LABEL : Cell Value, String Constant - oKcKWcv len=0 
' 0018     24 LABEL : Cell Value, String Constant - qepysPQqy len=0 
' 0018     23 LABEL : Cell Value, String Constant - stkvIHPu len=0 
' 0018     26 LABEL : Cell Value, String Constant - VpehepvtPoK len=0 
' 0018     23 LABEL : Cell Value, String Constant - XeiQysME len=0 
' 0018     26 LABEL : Cell Value, String Constant - zoGliDyobZm 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
' 
... (truncated)

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