Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 4155632e88707861…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:39:44 Authoring application: Microsoft Excel First seen: 2021-09-18
MD5: 6a1384a60fc16408c8ff1aee4f57553b SHA-1: a55ecec451b7fabcd21e2c3ee9c0c56b83a7f156 SHA-256: 4155632e88707861f4eae3fdfe735273076e5935092d50ce8b3435cd3e54df84
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open function, which is a critical finding indicating potential malicious execution. The presence of dangerous formula APIs like RUN suggests the macro is designed to execute commands. This points to an attack pattern where the macro is used to download and execute a secondary payload, a common technique 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) 6442 bytes
SHA-256: 304e8d933dbea093ef24e8a782452bd4bd96653b4d2837d4365895e3ad4b7bf2
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 -  nrmqp
' 0018     21 LABEL : Cell Value, String Constant - aHbebY len=0 
' 0018     25 LABEL : Cell Value, String Constant - AtAHzULeqZ len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C169 
' 0018     24 LABEL : Cell Value, String Constant - cOsUbqjdO len=0 
' 0018     24 LABEL : Cell Value, String Constant - doNUSWzXj len=0 
' 0018     22 LABEL : Cell Value, String Constant - EJRWecG len=0 
' 0018     27 LABEL : Cell Value, String Constant - ggFBacTpvBzu len=0 
' 0018     23 LABEL : Cell Value, String Constant - IoOclFtm len=0 
' 0018     25 LABEL : Cell Value, String Constant - JaDGbIsGSi len=0 
' 0018     25 LABEL : Cell Value, String Constant - mWYdLVEzmr len=0 
' 0018     21 LABEL : Cell Value, String Constant - nvLsxY len=0 
' 0018     22 LABEL : Cell Value, String Constant - PhBBLNU len=0 
' 0018     25 LABEL : Cell Value, String Constant - qnjsbIsQYt len=0 
' 0018     20 LABEL : Cell Value, String Constant - sAMjF len=0 
' 0018     24 LABEL : Cell Value, String Constant - tZhbjufRv len=0 
' 0018     23 LABEL : Cell Value, String Constant - VVSUkrZC len=0 
' 0018     27 LABEL : Cell Value, String Constant - xVXKwdnplccf len=0 
' 0018     27 LABEL : Cell Value, String Constant - YGczvLXPTnHa len=0 
' 0018     26 LABEL : Cell Value, String Constant - YyXmnsyhDWk len=0 
' 0018     21 LABEL : Cell Value, String Constant - ZdCeRv len=0 
' 0018     20 LABEL : Cell Value, String Constant - zQjcH 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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