Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 1f3b78cb31a66401…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-25 10:37:10 Authoring application: Microsoft Excel First seen: 2021-07-02
MD5: 78d8645e6e424f751be557264fa3dbb6 SHA-1: 28ccd54d5568b5ebfec38956d83c179c6d66d491 SHA-256: 1f3b78cb31a66401a1a88864136f99a6ef979d7c6c73f04343dcee4f8cdec956
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open function, which is a known method for executing malicious code upon opening the workbook. The presence of dangerous formula APIs like RUN indicates an intent to execute arbitrary commands. This technique is commonly used by macro-based malware to download and execute further stages.

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) 6415 bytes
SHA-256: 1c1021f6852c2211dfd83b17e03da6f69eeb27fe07fa2ef79173d468f79ea133
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     13 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  ZTYD
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!B154 
' 0018     25 LABEL : Cell Value, String Constant - axGoKozsaI len=0 
' 0018     25 LABEL : Cell Value, String Constant - CjgDuanDwv len=0 
' 0018     23 LABEL : Cell Value, String Constant - cVezWVkv len=0 
' 0018     21 LABEL : Cell Value, String Constant - EprUff len=0 
' 0018     20 LABEL : Cell Value, String Constant - hhDvk len=0 
' 0018     23 LABEL : Cell Value, String Constant - HVvgLNpN len=0 
' 0018     26 LABEL : Cell Value, String Constant - jjbXPMNELpd len=0 
' 0018     27 LABEL : Cell Value, String Constant - kCdJbrlDyOmF len=0 
' 0018     21 LABEL : Cell Value, String Constant - KkBZrs len=0 
' 0018     25 LABEL : Cell Value, String Constant - kMJATotItp len=0 
' 0018     27 LABEL : Cell Value, String Constant - kuAzGXbCpkFh len=0 
' 0018     25 LABEL : Cell Value, String Constant - mYYnbeNqen len=0 
' 0018     26 LABEL : Cell Value, String Constant - njBnwlrqkfu len=0 
' 0018     24 LABEL : Cell Value, String Constant - nuGdqmVwX len=0 
' 0018     27 LABEL : Cell Value, String Constant - OVkAWVJlRWPV len=0 
' 0018     24 LABEL : Cell Value, String Constant - tTjHuWjoY len=0 
' 0018     20 LABEL : Cell Value, String Constant - WiCug len=0 
' 0018     22 LABEL : Cell Value, String Constant - xyhKkiL len=0 
' 0018     21 LABEL : Cell Value, String Constant - ZSSlUU len=0 
' 0018     26 LABEL : Cell Value, String Constant - zupYzeGcdKh 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
' 00
... (truncated)

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