Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 1b8a3c62fc6df4aa…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:27:29 Authoring application: Microsoft Excel First seen: 2021-06-28
MD5: 26a40f1c634ba55fc4687f704ddba620 SHA-1: 33025823a9484b88bec757d6290f7bdd0c7898cf SHA-256: 1b8a3c62fc6df4aaca229c9c55bb8da10dfd5ee43668f310137c3cca1940d351
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 potential for arbitrary code execution. The presence of dangerous formula APIs like RUN further supports this. The macro sheet likely contains obfuscated code designed to download and execute a secondary payload, a common technique for initial access and further infection.

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) 6671 bytes
SHA-256: 886db822132b295b1f573ccd6b730c737338fc943b4c77edff97e8d1636d8cc1
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     20 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  YashTRqjYOv
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!H126 
' 0018     23 LABEL : Cell Value, String Constant - beyZswen len=0 
' 0018     22 LABEL : Cell Value, String Constant - ceEQyWC len=0 
' 0018     21 LABEL : Cell Value, String Constant - cIGznL len=0 
' 0018     25 LABEL : Cell Value, String Constant - ctfmngklaa len=0 
' 0018     27 LABEL : Cell Value, String Constant - eEcLTEpCOewK len=0 
' 0018     21 LABEL : Cell Value, String Constant - GnKAoL len=0 
' 0018     24 LABEL : Cell Value, String Constant - GrvVxJnxY len=0 
' 0018     24 LABEL : Cell Value, String Constant - IQTuoTKPn len=0 
' 0018     27 LABEL : Cell Value, String Constant - jnJWVvLXWEhf len=0 
' 0018     27 LABEL : Cell Value, String Constant - KQklAlYeKpRI len=0 
' 0018     27 LABEL : Cell Value, String Constant - mXbbgLgoJJcw len=0 
' 0018     26 LABEL : Cell Value, String Constant - nNdQHrtyoTS len=0 
' 0018     24 LABEL : Cell Value, String Constant - PcRbkxKoe len=0 
' 0018     22 LABEL : Cell Value, String Constant - pgwduoB len=0 
' 0018     22 LABEL : Cell Value, String Constant - RPyhJoH len=0 
' 0018     27 LABEL : Cell Value, String Constant - ssnZMIOzZuQv len=0 
' 0018     21 LABEL : Cell Value, String Constant - weFGxb len=0 
' 0018     20 LABEL : Cell Value, String Constant - xMcKg len=0 
' 0018     23 LABEL : Cell Value, String Constant - yMyZdFzc len=0 
' 0018     27 LABEL : Cell Value, String Constant - ZHzzCpWsfJjS 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/
... (truncated)

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