Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 f1f5aeb280e65bff…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-25 10:46:08 Authoring application: Microsoft Excel First seen: 2021-07-07
MD5: 42e072104afe8bccaae1b3d0496738d9 SHA-1: 35b88fe2210e8edc732af280442afbfc5928e0e8 SHA-256: f1f5aeb280e65bffc33c49c02f9eba4acd628beb1df58d6ab9a6ddb377d2c084
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 a known technique for executing malicious code upon opening the workbook. The macro sheet contains a call to a dangerous function, specifically `RUN=0`, suggesting it is intended to execute an external program. The document body contains obfuscated text, likely part of the macro's payload or a lure.

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) 6676 bytes
SHA-256: 2ad8df0fc3a2f744440b00dee2570468bcf6592db9acf5baff83392f3e333ccb
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 -  pZSRgcYQPp
' 0018     26 LABEL : Cell Value, String Constant - aAQqKTZNFde len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!B137 
' 0018     26 LABEL : Cell Value, String Constant - bUNtwXMkkdD len=0 
' 0018     27 LABEL : Cell Value, String Constant - CGbVexzJIAxy len=0 
' 0018     23 LABEL : Cell Value, String Constant - DaYFDKtW len=0 
' 0018     25 LABEL : Cell Value, String Constant - eDIbFrxMRH len=0 
' 0018     25 LABEL : Cell Value, String Constant - eykiRQgLYI len=0 
' 0018     22 LABEL : Cell Value, String Constant - GcBJhuF len=0 
' 0018     21 LABEL : Cell Value, String Constant - GXDRTp len=0 
' 0018     20 LABEL : Cell Value, String Constant - iJzpz len=0 
' 0018     20 LABEL : Cell Value, String Constant - LCacp len=0 
' 0018     26 LABEL : Cell Value, String Constant - lLLHuYRcCAH len=0 
' 0018     22 LABEL : Cell Value, String Constant - LxlYTex len=0 
' 0018     23 LABEL : Cell Value, String Constant - PPrlwuXa len=0 
' 0018     23 LABEL : Cell Value, String Constant - QuhAlpww len=0 
' 0018     24 LABEL : Cell Value, String Constant - WOpONMvlf len=0 
' 0018     27 LABEL : Cell Value, String Constant - WSEWsENRolAo len=0 
' 0018     22 LABEL : Cell Value, String Constant - xmpDKEn len=0 
' 0018     24 LABEL : Cell Value, String Constant - yPnmfCtEo len=0 
' 0018     23 LABEL : Cell Value, String Constant - ZkRpZvVp len=0 
' 0018     27 LABEL : Cell Value, String Constant - ZyyGEKqvBMGJ 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

... (truncated)

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