Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 aaf5b40ebbfd228b…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:43:14 Authoring application: Microsoft Excel First seen: 2021-09-18
MD5: e28c57c782024071e2a14b28bdcc2c15 SHA-1: 1cbc6082f0d2c77e8df1dc0c06ac7030c8a411aa SHA-256: aaf5b40ebbfd228b123edb56a4d8ca5e79eda4229f90605989848d439dd61b0a
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.005 Visual Basic

The file is an Excel document containing Excel 4.0 (XLM) macros. The presence of an Auto_Open defined name indicates that these macros will execute automatically upon opening the workbook. The critical heuristic firing for 'XLM Auto_Open with dangerous formula APIs' suggests the macros are designed to perform malicious actions, such as downloading and executing a payload. This is a common technique for initial access through spearphishing attachments.

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) 6818 bytes
SHA-256: e13a65834fdabbb5e903922ad0c14804f51cb8e120429260d6ac52ed4c949c44
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 -  baqnQLQlex
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!F150 
' 0018     26 LABEL : Cell Value, String Constant - bpaMbFrGAjs len=0 
' 0018     20 LABEL : Cell Value, String Constant - DYwtL len=0 
' 0018     20 LABEL : Cell Value, String Constant - eQbVL len=0 
' 0018     25 LABEL : Cell Value, String Constant - izPJSzASDh len=0 
' 0018     23 LABEL : Cell Value, String Constant - jvUWQfVM len=0 
' 0018     21 LABEL : Cell Value, String Constant - KcHWaR len=0 
' 0018     27 LABEL : Cell Value, String Constant - ngyIDDwfWSpV len=0 
' 0018     26 LABEL : Cell Value, String Constant - NhdZNaVMOVL len=0 
' 0018     25 LABEL : Cell Value, String Constant - noGFNlEZpR len=0 
' 0018     23 LABEL : Cell Value, String Constant - oaBSfcMo len=0 
' 0018     20 LABEL : Cell Value, String Constant - ohmQK len=0 
' 0018     26 LABEL : Cell Value, String Constant - sBDulUzVeLA len=0 
' 0018     21 LABEL : Cell Value, String Constant - SDZNbg len=0 
' 0018     21 LABEL : Cell Value, String Constant - sIJmVL len=0 
' 0018     26 LABEL : Cell Value, String Constant - soxoSqtSFuO len=0 
' 0018     25 LABEL : Cell Value, String Constant - TtMMCHkNRx len=0 
' 0018     26 LABEL : Cell Value, String Constant - URTwUHBOghD len=0 
' 0018     26 LABEL : Cell Value, String Constant - WlgVswoCkHf len=0 
' 0018     24 LABEL : Cell Value, String Constant - xcMGtEeBm len=0 
' 0018     21 LABEL : Cell Value, String Constant - ZwUiZH 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
' 00
... (truncated)

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