Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b747c99f036baefb…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:44:22 Authoring application: Microsoft Excel First seen: 2021-06-20
MD5: cef0229457b6e47b2a02505bad5ac471 SHA-1: 27cf59c26f9652a091af8dbf0529279837a8f0fe SHA-256: b747c99f036baefb4883413e859d8819f9ecf43ae83c392639dc70a6cd0d76c0
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 entry, which is a known method for executing malicious code. The macro sheet contains a reference to a dangerous formula API, specifically 'RUN', suggesting it is designed to execute external commands. The obfuscated document body content and the truncated script listing prevent a more detailed analysis of the payload, but the overall pattern points to a macro-based 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) 6751 bytes
SHA-256: 9bd4b2040f213b819a055bad5d5adcff88bd34fdc0807e19959215d00929a003
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     18 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  fSuAGmJFa
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E144 
' 0018     26 LABEL : Cell Value, String Constant - CWkBDjGaGyb len=0 
' 0018     21 LABEL : Cell Value, String Constant - DWvYAB len=0 
' 0018     27 LABEL : Cell Value, String Constant - ewukTBCqxKVN len=0 
' 0018     24 LABEL : Cell Value, String Constant - ghznBTFbp len=0 
' 0018     27 LABEL : Cell Value, String Constant - gRwTeQsFRnXD len=0 
' 0018     20 LABEL : Cell Value, String Constant - HIjqM len=0 
' 0018     24 LABEL : Cell Value, String Constant - HjiEmhcdm len=0 
' 0018     22 LABEL : Cell Value, String Constant - HUwHdck len=0 
' 0018     26 LABEL : Cell Value, String Constant - ihJFKQbqmIO len=0 
' 0018     21 LABEL : Cell Value, String Constant - JWkvyh len=0 
' 0018     22 LABEL : Cell Value, String Constant - kfJkazK len=0 
' 0018     24 LABEL : Cell Value, String Constant - LKwYpajQA len=0 
' 0018     24 LABEL : Cell Value, String Constant - MfVJhnqlE len=0 
' 0018     22 LABEL : Cell Value, String Constant - NKDNIKZ len=0 
' 0018     20 LABEL : Cell Value, String Constant - OODZr len=0 
' 0018     24 LABEL : Cell Value, String Constant - pnqCjxMGw len=0 
' 0018     20 LABEL : Cell Value, String Constant - wybDz len=0 
' 0018     22 LABEL : Cell Value, String Constant - xuqboeG len=0 
' 0018     21 LABEL : Cell Value, String Constant - XyoapE len=0 
' 0018     23 LABEL : Cell Value, String Constant - Yrphzetd 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 LAB
... (truncated)

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