Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 f1f4cfa5bb7d157c…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:38:01 Authoring application: Microsoft Excel First seen: 2021-07-07
MD5: ed3b4cf8242d190297be011eadd3e1ac SHA-1: 41c6b2a49c04734dc0f345f7debe2cfc07470b01 SHA-256: f1f4cfa5bb7d157c8c51efc8bb97c9d01d7da22a431c27428a7710b0fd0e9ccb
140 Risk Score

Malware Insights

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

This Excel file contains Excel 4.0 macros, specifically an Auto_Open function, which is a known technique for executing malicious code. The critical heuristic firings indicate the presence of dangerous formula APIs within the Auto_Open macro, suggesting it is designed to download and execute a secondary payload. No specific family could be identified from the available evidence.

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) 6563 bytes
SHA-256: 0928604e05a4673e0412c4493d995c13c5b26fda1162366bb7344b85b20a0fe5
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     19 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  TlChHuPIaC
' 0018     20 LABEL : Cell Value, String Constant - AIOzP len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A167 
' 0018     21 LABEL : Cell Value, String Constant - BKDpRV len=0 
' 0018     24 LABEL : Cell Value, String Constant - byDoLbZGL len=0 
' 0018     22 LABEL : Cell Value, String Constant - CLkSBJh len=0 
' 0018     24 LABEL : Cell Value, String Constant - DMvGZHZxs len=0 
' 0018     24 LABEL : Cell Value, String Constant - dvViZKtpB len=0 
' 0018     23 LABEL : Cell Value, String Constant - FxoTZPWM len=0 
' 0018     25 LABEL : Cell Value, String Constant - HQEJNqSsOB len=0 
' 0018     22 LABEL : Cell Value, String Constant - HyxYNuh len=0 
' 0018     20 LABEL : Cell Value, String Constant - jDDDJ len=0 
' 0018     26 LABEL : Cell Value, String Constant - LNvzHWkzpNL len=0 
' 0018     23 LABEL : Cell Value, String Constant - NLnHIHEX len=0 
' 0018     20 LABEL : Cell Value, String Constant - Nypbw len=0 
' 0018     25 LABEL : Cell Value, String Constant - qbrIHnrmnb len=0 
' 0018     22 LABEL : Cell Value, String Constant - sYnySCC len=0 
' 0018     25 LABEL : Cell Value, String Constant - VgkOYYOIwE len=0 
' 0018     25 LABEL : Cell Value, String Constant - vxZIslObHj len=0 
' 0018     20 LABEL : Cell Value, String Constant - wZfbh len=0 
' 0018     20 LABEL : Cell Value, String Constant - yaATY len=0 
' 0018     26 LABEL : Cell Value, String Constant - zmXEiXftjrC 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 LABEL
... (truncated)

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