Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b0dbee987e326027…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:44:08 Authoring application: Microsoft Excel First seen: 2021-10-07
MD5: c677f760280a7c2ae59f88697aeae331 SHA-1: 72afa307250e73e0be4b2b88af8bd017ca51c234 SHA-256: b0dbee987e3260273ecd44df6d1e388861b78aa68935b46a2577d120488ea140
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 defined name and dangerous formula APIs, specifically the RUN function. This strongly suggests the macro is designed to execute arbitrary code upon opening the document. While no specific URLs or hashes were extracted, the presence of XLM macros points to a downloader or initial execution stage of a malicious attack.

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) 6733 bytes
SHA-256: cdc0c0c3d71804cc00eee0b311361fe7efeff01c2042a2fccd845ccb499c8489
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     18 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  qkXkBNfLu
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!F165 
' 0018     26 LABEL : Cell Value, String Constant - awllNDWzTsI len=0 
' 0018     24 LABEL : Cell Value, String Constant - BQuJIcTQZ len=0 
' 0018     21 LABEL : Cell Value, String Constant - CemcTB len=0 
' 0018     24 LABEL : Cell Value, String Constant - ckpAJMzfI len=0 
' 0018     24 LABEL : Cell Value, String Constant - daFYGdoTv len=0 
' 0018     27 LABEL : Cell Value, String Constant - fCaQQzMJWRvu len=0 
' 0018     26 LABEL : Cell Value, String Constant - gdswUCQBBgk len=0 
' 0018     23 LABEL : Cell Value, String Constant - JAUxXaGW len=0 
' 0018     20 LABEL : Cell Value, String Constant - JKpuz len=0 
' 0018     27 LABEL : Cell Value, String Constant - mozGCvmDaLWC len=0 
' 0018     20 LABEL : Cell Value, String Constant - nAGDS len=0 
' 0018     24 LABEL : Cell Value, String Constant - SiRZwteyy len=0 
' 0018     27 LABEL : Cell Value, String Constant - SyYveguSTuxr len=0 
' 0018     23 LABEL : Cell Value, String Constant - TPbzASNI len=0 
' 0018     26 LABEL : Cell Value, String Constant - txfuiPiZKAj len=0 
' 0018     23 LABEL : Cell Value, String Constant - vJnzgjKK len=0 
' 0018     21 LABEL : Cell Value, String Constant - wrEEhe len=0 
' 0018     27 LABEL : Cell Value, String Constant - XsRyRewdISpv len=0 
' 0018     27 LABEL : Cell Value, String Constant - zlXuABxrBOGV len=0 
' 0018     26 LABEL : Cell Value, String Constant - ZVTKgizSePf 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 Const
... (truncated)

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