Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 56a20284c807762c…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:30:05 Authoring application: Microsoft Excel First seen: 2021-10-23
MD5: 5a762cc0137d51e786ca79423de3fe93 SHA-1: c2a85b4669ed92e2214c5cc65f2ebc701cceb9d5 SHA-256: 56a20284c807762ca8213bab3c2076f9e52de3fac48aa0a806efc6c5e6e2e4c8
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 entry, which is a common technique for executing malicious code upon opening the workbook. The macro sheet contains a reference to 'Auto_Open', suggesting it's designed to run automatically. The presence of dangerous formula APIs like RUN further confirms its malicious intent, likely to download and execute 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) 6465 bytes
SHA-256: 10723aa372ba35d8a31156a363c42890feacd6bfd8fe8aaede9df326c579ee32
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 -  XEy
' 0018     20 LABEL : Cell Value, String Constant - ARfog len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!B139 
' 0018     21 LABEL : Cell Value, String Constant - DhcIbU len=0 
' 0018     22 LABEL : Cell Value, String Constant - eGGeqHO len=0 
' 0018     27 LABEL : Cell Value, String Constant - GLxoMLOVZvqC len=0 
' 0018     23 LABEL : Cell Value, String Constant - hhtoHhMC len=0 
' 0018     20 LABEL : Cell Value, String Constant - iDdOw len=0 
' 0018     25 LABEL : Cell Value, String Constant - IGAMntEnVc len=0 
' 0018     23 LABEL : Cell Value, String Constant - iIgWUoqM len=0 
' 0018     24 LABEL : Cell Value, String Constant - JFOgUFvCu len=0 
' 0018     21 LABEL : Cell Value, String Constant - lVAHXj len=0 
' 0018     21 LABEL : Cell Value, String Constant - mZkEdu len=0 
' 0018     24 LABEL : Cell Value, String Constant - mzOHBVlTx len=0 
' 0018     27 LABEL : Cell Value, String Constant - qBZHsxiAGpnt len=0 
' 0018     21 LABEL : Cell Value, String Constant - qHezUb len=0 
' 0018     21 LABEL : Cell Value, String Constant - QNtmtz len=0 
' 0018     23 LABEL : Cell Value, String Constant - UeMUNVaJ len=0 
' 0018     20 LABEL : Cell Value, String Constant - WAGvN len=0 
' 0018     25 LABEL : Cell Value, String Constant - wIyetGVigC len=0 
' 0018     27 LABEL : Cell Value, String Constant - YuRYQSldUori len=0 
' 0018     26 LABEL : Cell Value, String Constant - ZGECarehckn 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 LABELSST
... (truncated)

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