Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 a8176bedfc29cd5a…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-25 10:34:35 Authoring application: Microsoft Excel First seen: 2021-09-16
MD5: 4d1787d46609b8f4a6999a4e6a2321b2 SHA-1: 3199452ffad6a7fa9859f7278e7399e85882607f SHA-256: a8176bedfc29cd5ad973ee4a84d163a5d722738e2257e274281fba6831539d6e
140 Risk Score

Malware Insights

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

The file is an Excel document containing Excel 4.0 macros, specifically triggering an Auto_Open function. This indicates an attempt to execute arbitrary code upon opening. The presence of dangerous formula APIs like RUN suggests the macro is designed to download and execute a secondary payload, a common technique for malware delivery.

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) 6437 bytes
SHA-256: f8af47195be16b4c445d47539606214f60226a328f7ccc5ea90f35e74412fc34
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 -  qlXvc
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!B137 
' 0018     25 LABEL : Cell Value, String Constant - cEZgsFEkHP len=0 
' 0018     20 LABEL : Cell Value, String Constant - Eusht len=0 
' 0018     25 LABEL : Cell Value, String Constant - GJBlrqhKRl len=0 
' 0018     27 LABEL : Cell Value, String Constant - hFTlrOHcttvS len=0 
' 0018     22 LABEL : Cell Value, String Constant - HNShXkC len=0 
' 0018     24 LABEL : Cell Value, String Constant - iDTEdIgUE len=0 
' 0018     20 LABEL : Cell Value, String Constant - IhdVy len=0 
' 0018     23 LABEL : Cell Value, String Constant - ImgSnRRo len=0 
' 0018     27 LABEL : Cell Value, String Constant - kcMSePzKEdrH len=0 
' 0018     25 LABEL : Cell Value, String Constant - LAAOgTSPqh len=0 
' 0018     20 LABEL : Cell Value, String Constant - lPnnw len=0 
' 0018     24 LABEL : Cell Value, String Constant - MnydOLLVB len=0 
' 0018     24 LABEL : Cell Value, String Constant - pKjHJMVas len=0 
' 0018     26 LABEL : Cell Value, String Constant - SaktANlvenI len=0 
' 0018     23 LABEL : Cell Value, String Constant - tdGRlAeJ len=0 
' 0018     23 LABEL : Cell Value, String Constant - UtBFRdcq len=0 
' 0018     26 LABEL : Cell Value, String Constant - WATEFlxSjsh len=0 
' 0018     22 LABEL : Cell Value, String Constant - wqGMHzB len=0 
' 0018     21 LABEL : Cell Value, String Constant - xAYyzr len=0 
' 0018     23 LABEL : Cell Value, String Constant - ywxyWpmo 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     
... (truncated)

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