Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 875f87b91cb88ed0…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:35:22 Authoring application: Microsoft Excel First seen: 2021-05-22
MD5: a96a3f72e08e917ebcc3535cf61abbe9 SHA-1: d137efa9fdf0a5dae473242efd234e4f9c87a1aa SHA-256: 875f87b91cb88ed0719e3b8d559c82a29a2ec5bcf82e6215fcec8e48cdf2d1d3
140 Risk Score

Malware Insights

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

The sample is an Excel file containing Excel 4.0 macros, specifically an Auto_Open function. This function is designed to execute arbitrary code upon opening the document, which is a common technique for delivering malicious payloads. The presence of dangerous formula APIs further indicates malicious intent.

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) 6627 bytes
SHA-256: ef2a5d46bc00ec2d0ff0cbfa1822b7716ecef9166c9514f44291dc0934aa8481
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 -  qFqRoVUEU
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!B191 
' 0018     23 LABEL : Cell Value, String Constant - CFyzvGxp len=0 
' 0018     27 LABEL : Cell Value, String Constant - cjcEisZkNveG len=0 
' 0018     26 LABEL : Cell Value, String Constant - ELXIXyRexGj len=0 
' 0018     26 LABEL : Cell Value, String Constant - fQMdeAhaEpy len=0 
' 0018     21 LABEL : Cell Value, String Constant - gXuLMN len=0 
' 0018     26 LABEL : Cell Value, String Constant - JMSPhQvDsYh len=0 
' 0018     25 LABEL : Cell Value, String Constant - LUCOvZSlex len=0 
' 0018     24 LABEL : Cell Value, String Constant - nCeZVFYFT len=0 
' 0018     25 LABEL : Cell Value, String Constant - NeRrVBumGp len=0 
' 0018     26 LABEL : Cell Value, String Constant - ptoitGJzofQ len=0 
' 0018     24 LABEL : Cell Value, String Constant - PzjpECvLi len=0 
' 0018     25 LABEL : Cell Value, String Constant - QaEboyJyRi len=0 
' 0018     25 LABEL : Cell Value, String Constant - QNrwSAXThG len=0 
' 0018     24 LABEL : Cell Value, String Constant - rCxMjlcwi len=0 
' 0018     24 LABEL : Cell Value, String Constant - rvrodAEyw len=0 
' 0018     21 LABEL : Cell Value, String Constant - SQluFu len=0 
' 0018     27 LABEL : Cell Value, String Constant - vlJWCTXpPTLz len=0 
' 0018     22 LABEL : Cell Value, String Constant - XqYFPMi len=0 
' 0018     22 LABEL : Cell Value, String Constant - ZHvfCzd len=0 
' 0018     25 LABEL : Cell Value, String Constant - ZVaTixXWEc 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 Con
... (truncated)

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