Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b6683dec82991fbe…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:46:03 Authoring application: Microsoft Excel First seen: 2021-07-07
MD5: b8c854168ba8813a3f8aefd398154dff SHA-1: b5684dd664bbc03ab6deadbd8f8f6016b4b29b2f SHA-256: b6683dec82991fbe5fe1e0ea847c40a788d0b225c22424a9ccfb7109ea4292c3
140 Risk Score

Malware Insights

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

The sample is an Excel file containing Excel 4.0 (XLM) macros. The presence of an Auto_Open defined name and the use of dangerous formula APIs like RUN indicate that the macros are intended to execute automatically when the workbook is opened. This is a common technique for downloading and executing 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) 6604 bytes
SHA-256: 7b0dfad5c7ddad528276bd06988bd12dfc12f5885c8157771ec96b1247f30b4e
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     17 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  YxrukyDi
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!B167 
' 0018     27 LABEL : Cell Value, String Constant - DgNJPkLgoMrY len=0 
' 0018     27 LABEL : Cell Value, String Constant - drUFKyiMCkYk len=0 
' 0018     25 LABEL : Cell Value, String Constant - geAwPUWocf len=0 
' 0018     25 LABEL : Cell Value, String Constant - ibDHbAGpzR len=0 
' 0018     26 LABEL : Cell Value, String Constant - IHnOyKmfYki len=0 
' 0018     25 LABEL : Cell Value, String Constant - jWEtcFLazz len=0 
' 0018     23 LABEL : Cell Value, String Constant - kOGkbpBK len=0 
' 0018     25 LABEL : Cell Value, String Constant - nhysmmqtUn len=0 
' 0018     20 LABEL : Cell Value, String Constant - OODzw len=0 
' 0018     21 LABEL : Cell Value, String Constant - qmNGeE len=0 
' 0018     21 LABEL : Cell Value, String Constant - TQSbxR len=0 
' 0018     23 LABEL : Cell Value, String Constant - ulzQOJyE len=0 
' 0018     27 LABEL : Cell Value, String Constant - UreUWVIlEPqY len=0 
' 0018     23 LABEL : Cell Value, String Constant - VsWtEtHV len=0 
' 0018     22 LABEL : Cell Value, String Constant - WFsZDxi len=0 
' 0018     21 LABEL : Cell Value, String Constant - xveUEA len=0 
' 0018     22 LABEL : Cell Value, String Constant - xWuGuWa len=0 
' 0018     22 LABEL : Cell Value, String Constant - YgoyLnV len=0 
' 0018     23 LABEL : Cell Value, String Constant - zICiSluK len=0 
' 0018     25 LABEL : Cell Value, String Constant - zKowVYdywa 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
' 00f
... (truncated)

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