Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 f7e8bc6f2bfce486…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:31:51 Authoring application: Microsoft Excel First seen: 2021-07-02
MD5: 439adba879126922e8e2c31213998884 SHA-1: 37bc538c28b1cab907d3f6d6c4110fe27d709cc1 SHA-256: f7e8bc6f2bfce486857b1097574132f9f467a2bb335ea5cecc13335b3680e912
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 defined name, which is configured to use dangerous formula APIs. This strongly suggests the macro is designed to automatically execute malicious code upon opening the workbook. The macro sheet itself contains numerous obfuscated strings and references to potentially dangerous functions, indicating an attempt to download and execute a secondary payload.

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) 6337 bytes
SHA-256: 6a867402c47f5ba1b6599e341c679270424faf5cbb0309a8d8d65a6f2ef01dbb
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 -  zdy
' 0018     23 LABEL : Cell Value, String Constant - AGageBcN len=0 
' 0018     23 LABEL : Cell Value, String Constant - aijhxBmR len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!H161 
' 0018     23 LABEL : Cell Value, String Constant - CxgbiLFm len=0 
' 0018     26 LABEL : Cell Value, String Constant - fhIWQiqiljy len=0 
' 0018     23 LABEL : Cell Value, String Constant - flHQIZgk len=0 
' 0018     24 LABEL : Cell Value, String Constant - FoQWCJwAM len=0 
' 0018     22 LABEL : Cell Value, String Constant - GnLsAwV len=0 
' 0018     20 LABEL : Cell Value, String Constant - gXzDz len=0 
' 0018     22 LABEL : Cell Value, String Constant - IQMTocp len=0 
' 0018     21 LABEL : Cell Value, String Constant - iSYlOA len=0 
' 0018     21 LABEL : Cell Value, String Constant - jBDnAL len=0 
' 0018     23 LABEL : Cell Value, String Constant - kGmfUAsW len=0 
' 0018     24 LABEL : Cell Value, String Constant - lvhqBuWVE len=0 
' 0018     22 LABEL : Cell Value, String Constant - NsNJgXE len=0 
' 0018     22 LABEL : Cell Value, String Constant - oNmOXbG len=0 
' 0018     21 LABEL : Cell Value, String Constant - QYQDuC len=0 
' 0018     23 LABEL : Cell Value, String Constant - URANWbdA len=0 
' 0018     27 LABEL : Cell Value, String Constant - vphCBEKAlwVB len=0 
' 0018     24 LABEL : Cell Value, String Constant - wOjkChaaV len=0 
' 0018     21 LABEL : Cell Value, String Constant - ZhauyW 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 LABELSST : Cel
... (truncated)

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