Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 ef934e3ee61ebe67…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:39:43 Authoring application: Microsoft Excel First seen: 2021-06-13
MD5: 5a344eaa45c58c0cf9c06d7af958799e SHA-1: 374c6a42024b3d5572e5c46fb5bb46186b475d84 SHA-256: ef934e3ee61ebe67ca582eaecfb314e94b4fac36d0005b8619c8485a0a7df06d
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 point, which is a common technique for executing malicious code within Office documents. The macro sheet itself contains a large amount of obfuscated data, suggesting it is designed to perform actions beyond simple calculations. The Auto_Open function is likely used to execute a second-stage payload or exploit.

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) 6847 bytes
SHA-256: 993951f57464732d68540d4ebcd0b4e6cd6b7d26de632da7cc615a9a6321c8be
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 -  mBHNTMWYM
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C182 
' 0018     27 LABEL : Cell Value, String Constant - emFjhlkTGYQr len=0 
' 0018     21 LABEL : Cell Value, String Constant - GNMBDP len=0 
' 0018     24 LABEL : Cell Value, String Constant - iApsTFhgq len=0 
' 0018     20 LABEL : Cell Value, String Constant - kXjzM len=0 
' 0018     24 LABEL : Cell Value, String Constant - lZiSugSRz len=0 
' 0018     26 LABEL : Cell Value, String Constant - MHYpTkEdWhx len=0 
' 0018     26 LABEL : Cell Value, String Constant - NaQpdDHpGHL len=0 
' 0018     26 LABEL : Cell Value, String Constant - nJmWLAhmAsx len=0 
' 0018     20 LABEL : Cell Value, String Constant - qqmoA len=0 
' 0018     22 LABEL : Cell Value, String Constant - RAEEtoS len=0 
' 0018     24 LABEL : Cell Value, String Constant - tycuHWGBr len=0 
' 0018     22 LABEL : Cell Value, String Constant - urbytQe len=0 
' 0018     23 LABEL : Cell Value, String Constant - wgLgsMFt len=0 
' 0018     27 LABEL : Cell Value, String Constant - wnhBkprqXikS len=0 
' 0018     25 LABEL : Cell Value, String Constant - YOmLopYZbH len=0 
' 0018     22 LABEL : Cell Value, String Constant - YPYBBLM len=0 
' 0018     21 LABEL : Cell Value, String Constant - ZbMJGj len=0 
' 0018     21 LABEL : Cell Value, String Constant - zcPsbR len=0 
' 0018     23 LABEL : Cell Value, String Constant - ZmeteEKw len=0 
' 0018     23 LABEL : Cell Value, String Constant - zSjCmhyh 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    
... (truncated)

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