Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 f8a8a9ddc64e87be…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:40:17 Authoring application: Microsoft Excel First seen: 2021-07-13
MD5: f1c9fa83d068f0aba181fe400c09e773 SHA-1: 1411ec085ef13cecc0fc928f28a61fb812ebc276 SHA-256: f8a8a9ddc64e87be20a511f70234e1d01696e7ead70b5265a62b6fb304783812
140 Risk Score

Malware Insights

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

The sample is an Excel file containing Excel 4.0 macros, specifically an Auto_Open function. This function is designed to automatically execute code when the workbook is opened, indicating a likely attempt to run a malicious payload. The presence of dangerous formula APIs further supports this assessment.

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) 6645 bytes
SHA-256: d437da39c360a70229449c4cfd82b6fde5977b3927d59bb78c9cf2036b61a4e3
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     14 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  uKCXG
' 0018     26 LABEL : Cell Value, String Constant - AarcypwhojD len=0 
' 0018     22 LABEL : Cell Value, String Constant - adFejYe len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!H136 
' 0018     20 LABEL : Cell Value, String Constant - AxcRZ len=0 
' 0018     21 LABEL : Cell Value, String Constant - cBhOxm len=0 
' 0018     24 LABEL : Cell Value, String Constant - cBJJEYiTU len=0 
' 0018     24 LABEL : Cell Value, String Constant - KzNruGlxy len=0 
' 0018     21 LABEL : Cell Value, String Constant - mlCRVT len=0 
' 0018     22 LABEL : Cell Value, String Constant - mOaiFdH len=0 
' 0018     24 LABEL : Cell Value, String Constant - nfIRoSNpQ len=0 
' 0018     25 LABEL : Cell Value, String Constant - NUZRHlGtBm len=0 
' 0018     26 LABEL : Cell Value, String Constant - pcklxHqZCxH len=0 
' 0018     24 LABEL : Cell Value, String Constant - RkWEtFqyB len=0 
' 0018     20 LABEL : Cell Value, String Constant - SvcFc len=0 
' 0018     21 LABEL : Cell Value, String Constant - UJExXH len=0 
' 0018     22 LABEL : Cell Value, String Constant - Uruovuv len=0 
' 0018     23 LABEL : Cell Value, String Constant - VodLrTWU len=0 
' 0018     26 LABEL : Cell Value, String Constant - WzPirkyAPyE len=0 
' 0018     21 LABEL : Cell Value, String Constant - XHLVGg len=0 
' 0018     22 LABEL : Cell Value, String Constant - xYZKpQA len=0 
' 0018     26 LABEL : Cell Value, String Constant - YcEhseHNbau 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 LABELSS
... (truncated)

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