Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 e59d30f2525b488f…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-25 10:45:59 Authoring application: Microsoft Excel First seen: 2021-06-20
MD5: 82658d85ce14229bce205545740b65ff SHA-1: 0c29ddffe79bad51c3d0479fb82dc2c690f6a532 SHA-256: e59d30f2525b488fe4e814ca058be0d70d75f0154752c085b7c0e39b2f2386f9
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, and specifically that these macros call dangerous functions like RUN. This strongly suggests the macro is designed to execute arbitrary code upon opening the document. The macro sheet itself contains a large amount of obfuscated data, likely containing the payload or instructions for downloading it.

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) 6569 bytes
SHA-256: a6dbf64c24341060527320c723219fdbee281b2d68cfb7c1393d44c5fb1f4f08
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 -  OIsykUDP
' 0018     24 LABEL : Cell Value, String Constant - aenFeHWqu len=0 
' 0018     26 LABEL : Cell Value, String Constant - APDqdDtDxoN len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A181 
' 0018     22 LABEL : Cell Value, String Constant - BHPHevs len=0 
' 0018     24 LABEL : Cell Value, String Constant - cerbIriBn len=0 
' 0018     27 LABEL : Cell Value, String Constant - FtACVTUxFmSt len=0 
' 0018     22 LABEL : Cell Value, String Constant - kjjMiAM len=0 
' 0018     24 LABEL : Cell Value, String Constant - MHweGczvL len=0 
' 0018     24 LABEL : Cell Value, String Constant - MqUxQqcAH len=0 
' 0018     23 LABEL : Cell Value, String Constant - NHxwXDsJ len=0 
' 0018     23 LABEL : Cell Value, String Constant - ocPoleno len=0 
' 0018     25 LABEL : Cell Value, String Constant - QaEpZaMSsw len=0 
' 0018     20 LABEL : Cell Value, String Constant - qbnFN len=0 
' 0018     27 LABEL : Cell Value, String Constant - qpzqLuWPRuzU len=0 
' 0018     27 LABEL : Cell Value, String Constant - RPnuYpNUFrGX len=0 
' 0018     26 LABEL : Cell Value, String Constant - SUtHMbRvapU len=0 
' 0018     20 LABEL : Cell Value, String Constant - uKzAq len=0 
' 0018     24 LABEL : Cell Value, String Constant - upIOHkFgX len=0 
' 0018     27 LABEL : Cell Value, String Constant - vcRkrWBHtCqC len=0 
' 0018     20 LABEL : Cell Value, String Constant - xbcky len=0 
' 0018     23 LABEL : Cell Value, String Constant - xqPCzXFS 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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