Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c3e883f1663e1a62…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:38:53 Authoring application: Microsoft Excel First seen: 2021-06-28
MD5: 1073a999941a18efbb2d4f151326c371 SHA-1: 0d1443ad808993aaea046fdabd0434c7e3f7852b SHA-256: c3e883f1663e1a626060d4b06c92e55dfe89d616b435cf9537ec434357db32ff
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. Heuristics indicate the presence of an Auto_Open macro, which is a common technique for automatically executing malicious code when the workbook is opened. The macro sheet contains formulas that call dangerous API functions, suggesting an intent to download and execute a second-stage payload. No specific family could be identified.

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) 6743 bytes
SHA-256: 4105a54e253f8f36c3bdf03e3bbe8891570b7e789642b4ffff1fd97176819111
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     16 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  hFvJaqU
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C186 
' 0018     26 LABEL : Cell Value, String Constant - ciaEZKrJTaJ len=0 
' 0018     23 LABEL : Cell Value, String Constant - eCUDAwDJ len=0 
' 0018     23 LABEL : Cell Value, String Constant - gfroEGTJ len=0 
' 0018     24 LABEL : Cell Value, String Constant - hPhzWCJtM len=0 
' 0018     22 LABEL : Cell Value, String Constant - IMouuXK len=0 
' 0018     24 LABEL : Cell Value, String Constant - kLXXbwnjv len=0 
' 0018     21 LABEL : Cell Value, String Constant - LvrfPb len=0 
' 0018     23 LABEL : Cell Value, String Constant - MeImmUKO len=0 
' 0018     25 LABEL : Cell Value, String Constant - mIbfRSabyD len=0 
' 0018     26 LABEL : Cell Value, String Constant - MPFYcRyRETd len=0 
' 0018     27 LABEL : Cell Value, String Constant - nkXvPxGPbvzJ len=0 
' 0018     26 LABEL : Cell Value, String Constant - NLmYOpUECYX len=0 
' 0018     20 LABEL : Cell Value, String Constant - NsXAm len=0 
' 0018     26 LABEL : Cell Value, String Constant - QRAUaSPRfYo len=0 
' 0018     21 LABEL : Cell Value, String Constant - QrmDHT len=0 
' 0018     25 LABEL : Cell Value, String Constant - rDgvoJWZTk len=0 
' 0018     24 LABEL : Cell Value, String Constant - rnQQQwjAj len=0 
' 0018     24 LABEL : Cell Value, String Constant - uGVKQZfHo len=0 
' 0018     27 LABEL : Cell Value, String Constant - XwJESLSATkww len=0 
' 0018     26 LABEL : Cell Value, String Constant - zGULTchAcon 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/ 
... (truncated)

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