Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 daee2fcaa4f82896…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:38:41 Authoring application: Microsoft Excel First seen: 2021-09-17
MD5: c8a4113d84765da4c76401b0691c771b SHA-1: e5c63577df5a36ecb31531e175d50cad4c80f9e2 SHA-256: daee2fcaa4f828961719fb107205e2d67f3cf08faca9ce70898a51cf682f672f
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 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. While the exact payload is not clear due to truncation, the mechanism points to a macro-based execution of a secondary payload.

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) 6455 bytes
SHA-256: 3dc9b34d429314d6c61ac8daa64c07e4029427b598cd144c625fe95e447fe3b6
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     15 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  CmKYyS
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C159 
' 0018     27 LABEL : Cell Value, String Constant - AvArGllGdLUM len=0 
' 0018     20 LABEL : Cell Value, String Constant - BtHbS len=0 
' 0018     21 LABEL : Cell Value, String Constant - btYsks len=0 
' 0018     23 LABEL : Cell Value, String Constant - DGheNbfQ len=0 
' 0018     24 LABEL : Cell Value, String Constant - FfOPmrANH len=0 
' 0018     26 LABEL : Cell Value, String Constant - gGjHigCQcnI len=0 
' 0018     23 LABEL : Cell Value, String Constant - GiuZPLjw len=0 
' 0018     25 LABEL : Cell Value, String Constant - GVmQnSLDVI len=0 
' 0018     20 LABEL : Cell Value, String Constant - lnnNz len=0 
' 0018     21 LABEL : Cell Value, String Constant - MGJjtB len=0 
' 0018     24 LABEL : Cell Value, String Constant - moEVomgBS len=0 
' 0018     27 LABEL : Cell Value, String Constant - RIAjoaKMbCsn len=0 
' 0018     22 LABEL : Cell Value, String Constant - shNTSbW len=0 
' 0018     25 LABEL : Cell Value, String Constant - TTrsuuyXCt len=0 
' 0018     26 LABEL : Cell Value, String Constant - uDjvORAoGcf len=0 
' 0018     22 LABEL : Cell Value, String Constant - VnOeIxi len=0 
' 0018     20 LABEL : Cell Value, String Constant - wkOYW len=0 
' 0018     22 LABEL : Cell Value, String Constant - xlmprMK len=0 
' 0018     20 LABEL : Cell Value, String Constant - XxhnD len=0 
' 0018     23 LABEL : Cell Value, String Constant - YqZpIBfx 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 LABEL
... (truncated)

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