Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 d53effb18bb128c7…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:45:55 Authoring application: Microsoft Excel First seen: 2021-09-18
MD5: 7b89dcb413e6c33eefe46a147c1cc09e SHA-1: cb05a5f5964ffef74d12c45348d6967f6a7e84e5 SHA-256: d53effb18bb128c763ad2b6ec90b1cabf5d05ed65e06d43ec588714b0fff9f37
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file is an Excel 4.0 macro-enabled workbook containing an Auto_Open function, which is a critical finding indicating automatic execution upon opening. The presence of dangerous formula APIs within the Auto_Open macro suggests it is designed to execute arbitrary code, likely for downloading and running a second-stage payload. No specific family could be identified, but the technique is common for initial payload delivery.

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) 6596 bytes
SHA-256: cabb85295ceb15a9bdfa0ddff37254e378a2c72bd98d0aa969e0df1b6a2d6110
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 -  ioU
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C149 
' 0018     22 LABEL : Cell Value, String Constant - cHisZyS len=0 
' 0018     21 LABEL : Cell Value, String Constant - dvgMHk len=0 
' 0018     25 LABEL : Cell Value, String Constant - hIbCqpMQWm len=0 
' 0018     27 LABEL : Cell Value, String Constant - kUYfcqMeALwQ len=0 
' 0018     25 LABEL : Cell Value, String Constant - nRhDXMuriD len=0 
' 0018     27 LABEL : Cell Value, String Constant - NVpnzwoPXfbN len=0 
' 0018     25 LABEL : Cell Value, String Constant - OBgKAXQxfK len=0 
' 0018     24 LABEL : Cell Value, String Constant - oilOcthmk len=0 
' 0018     27 LABEL : Cell Value, String Constant - OKJUpdmQYHEv len=0 
' 0018     24 LABEL : Cell Value, String Constant - OVeeegqXO len=0 
' 0018     20 LABEL : Cell Value, String Constant - ppnBZ len=0 
' 0018     26 LABEL : Cell Value, String Constant - qlDDrZbatPT len=0 
' 0018     25 LABEL : Cell Value, String Constant - qRzDjxiWlu len=0 
' 0018     22 LABEL : Cell Value, String Constant - RFJTbDJ len=0 
' 0018     24 LABEL : Cell Value, String Constant - uDznItnNh len=0 
' 0018     26 LABEL : Cell Value, String Constant - UfvzGqiIFgO len=0 
' 0018     20 LABEL : Cell Value, String Constant - vBysW len=0 
' 0018     27 LABEL : Cell Value, String Constant - XfzZFOLmjyas len=0 
' 0018     22 LABEL : Cell Value, String Constant - ZJGrOOC len=0 
' 0018     26 LABEL : Cell Value, String Constant - zoVtnzgTexM 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/ SS
... (truncated)

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