Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b1be581749738fc7…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:47:17 Authoring application: Microsoft Excel First seen: 2020-12-25
MD5: 6bc64425a02a7b88268c84538e93812c SHA-1: bb6e02926de7c455dc9ba6f630eb792552cdd83b SHA-256: b1be581749738fc7af7dd92a8beffc89997be679453542d7b89ec5b77dc0b43f
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open defined name, which is a common technique for executing malicious code upon opening the document. The macro sheet contains a reference to a dangerous formula API, suggesting it is designed to run arbitrary commands. The presence of XLM macros points to an attempt to execute a secondary 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) 6566 bytes
SHA-256: 0f044cde79794a09f9b5631796e5c3ff31a894a25ff7d9aa20e9845316e958da
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     19 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  ZlELOVmVav
' 0018     25 LABEL : Cell Value, String Constant - aLVWVOvQCb len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!H165 
' 0018     21 LABEL : Cell Value, String Constant - CSdLgp len=0 
' 0018     24 LABEL : Cell Value, String Constant - CuoYoODKp len=0 
' 0018     23 LABEL : Cell Value, String Constant - CUZWjzia len=0 
' 0018     26 LABEL : Cell Value, String Constant - ewgSGZWIVav len=0 
' 0018     22 LABEL : Cell Value, String Constant - gnBLSqO len=0 
' 0018     23 LABEL : Cell Value, String Constant - hZCpCkgw len=0 
' 0018     21 LABEL : Cell Value, String Constant - IgwwUN len=0 
' 0018     23 LABEL : Cell Value, String Constant - kURAjHeH len=0 
' 0018     20 LABEL : Cell Value, String Constant - MSkUD len=0 
' 0018     22 LABEL : Cell Value, String Constant - NFCSRLk len=0 
' 0018     21 LABEL : Cell Value, String Constant - NHFsFR len=0 
' 0018     26 LABEL : Cell Value, String Constant - nzuKlVlMeSe len=0 
' 0018     26 LABEL : Cell Value, String Constant - OaneKHLriGq len=0 
' 0018     26 LABEL : Cell Value, String Constant - qLMiyThOsml len=0 
' 0018     20 LABEL : Cell Value, String Constant - QURWX len=0 
' 0018     23 LABEL : Cell Value, String Constant - xLYVxrBi len=0 
' 0018     20 LABEL : Cell Value, String Constant - xtyid len=0 
' 0018     27 LABEL : Cell Value, String Constant - YQZvJzYDbuJu len=0 
' 0018     22 LABEL : Cell Value, String Constant - YvaUmlH 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 L
... (truncated)

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