Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 99f515dfd6db2f98…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:47:09 Authoring application: Microsoft Excel First seen: 2021-07-02
MD5: 35b86c8cc0179515dc4183f3da592b14 SHA-1: 01b893dc197acd6a604258e68dbd9847644db65d SHA-256: 99f515dfd6db2f987a947c7a85af9f6c8092cb73cdbc75986c23c78a1a2b99ea
140 Risk Score

Malware Insights

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

The sample contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding indicating automatic execution upon opening. The presence of dangerous formula APIs like RUN suggests the macro is designed to execute arbitrary commands, likely to download and run a second-stage payload. No specific family could be identified, but the technique is common for initial execution.

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) 6543 bytes
SHA-256: 61f9d4cd14627d4183a21a741f921c75296d50e93354d4066c83bbe3366a3b7c
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     12 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  dAf
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!B135 
' 0018     21 LABEL : Cell Value, String Constant - AyXilX len=0 
' 0018     22 LABEL : Cell Value, String Constant - cepeAik len=0 
' 0018     25 LABEL : Cell Value, String Constant - CmeHRCSkkP len=0 
' 0018     26 LABEL : Cell Value, String Constant - czPnxikxCRs len=0 
' 0018     21 LABEL : Cell Value, String Constant - ELuynb len=0 
' 0018     20 LABEL : Cell Value, String Constant - fPpZa len=0 
' 0018     27 LABEL : Cell Value, String Constant - HuQTiKlkzLuU len=0 
' 0018     24 LABEL : Cell Value, String Constant - JaimjAQsl len=0 
' 0018     27 LABEL : Cell Value, String Constant - JFcfXkOqvzRg len=0 
' 0018     24 LABEL : Cell Value, String Constant - JivANhUgI len=0 
' 0018     23 LABEL : Cell Value, String Constant - MguePREF len=0 
' 0018     27 LABEL : Cell Value, String Constant - NBjQrPbwuSUx len=0 
' 0018     20 LABEL : Cell Value, String Constant - NJwUV len=0 
' 0018     21 LABEL : Cell Value, String Constant - nMQaXs len=0 
' 0018     22 LABEL : Cell Value, String Constant - pQiieXn len=0 
' 0018     23 LABEL : Cell Value, String Constant - rOsUvAjZ len=0 
' 0018     21 LABEL : Cell Value, String Constant - wwkdYj len=0 
' 0018     22 LABEL : Cell Value, String Constant - yIUlFZN len=0 
' 0018     24 LABEL : Cell Value, String Constant - YLhwVmaJb len=0 
' 0018     27 LABEL : Cell Value, String Constant - yXudqgNTeYNZ 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 LA
... (truncated)

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