Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 12904bdbeb8273f5…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:41:04 Authoring application: Microsoft Excel First seen: 2021-07-10
MD5: 06f75c762b4380868da4b54d0326ce7d SHA-1: b52203d87a4d837a65be8b587dcd649227bac711 SHA-256: 12904bdbeb8273f524b5e6b824ecabc56670cb6fcbad26f9eb4bb98a849a53d9
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 code, likely 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) 6575 bytes
SHA-256: baf67f5801ebe0a06c29bc7e6e811fe0689bc85d566ef3a442aad6bcec9c7c0a
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 -  FjG
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!G173 
' 0018     20 LABEL : Cell Value, String Constant - BcKbe len=0 
' 0018     27 LABEL : Cell Value, String Constant - CveClDIhYlEm len=0 
' 0018     20 LABEL : Cell Value, String Constant - DtOHS len=0 
' 0018     25 LABEL : Cell Value, String Constant - EiuOjIcXIC len=0 
' 0018     26 LABEL : Cell Value, String Constant - EQpoWSCCgwR len=0 
' 0018     24 LABEL : Cell Value, String Constant - HRrbJnyzW len=0 
' 0018     25 LABEL : Cell Value, String Constant - KwDxrQfdnZ len=0 
' 0018     25 LABEL : Cell Value, String Constant - lVHmclwPqu len=0 
' 0018     26 LABEL : Cell Value, String Constant - lZamWCIsOkF len=0 
' 0018     24 LABEL : Cell Value, String Constant - nbPwTUGcw len=0 
' 0018     24 LABEL : Cell Value, String Constant - OtBeOWVhD len=0 
' 0018     21 LABEL : Cell Value, String Constant - oxODEk len=0 
' 0018     27 LABEL : Cell Value, String Constant - pfarutYfRjBD len=0 
' 0018     24 LABEL : Cell Value, String Constant - RDIepmmvQ len=0 
' 0018     20 LABEL : Cell Value, String Constant - ssCIn len=0 
' 0018     27 LABEL : Cell Value, String Constant - tayrpBPUsOvL len=0 
' 0018     20 LABEL : Cell Value, String Constant - tiyUK len=0 
' 0018     20 LABEL : Cell Value, String Constant - tqrZD len=0 
' 0018     25 LABEL : Cell Value, String Constant - VOsWZVXWGb len=0 
' 0018     26 LABEL : Cell Value, String Constant - zzMTMlYloWF 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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