Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 90a20e435f0f6732…

MALICIOUS

Office (OLE)

202.0 KB Created: 2020-07-16 08:15:40 Authoring application: Microsoft Excel First seen: 2020-09-15
MD5: 9b2425e675ba07c85f76bb01186d9ba2 SHA-1: db96d1db7235549ca1a5d4a9c1c4676b7249d9dc SHA-256: 90a20e435f0f6732b85abee8b8f5511d307501320d55d51fa35a3eaf792b58aa
220 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The sample is an Excel file containing Excel 4.0 (XLM) macros, specifically an Auto_Open defined name, which is a critical finding. The macros also employ environment evasion techniques and use dangerous formula APIs like RUN. The presence of a macro-enable lure further indicates malicious intent. The XLM macros are designed to execute automatically upon opening, likely to download and execute a secondary payload.

Heuristics 5

  • 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.
  • XLM Auto_Open environment-evasion close gate critical OLE_XLM_ENVIRONMENT_EVASION_CLOSE
    Excel 4.0 macro sheet auto-executes environment checks with GET.WORKSPACE / GET.WINDOW, then shows a fake corruption/error message and closes the workbook when the host fails those checks. This is a malware sandbox-evasion pattern, even when the later payload stage is hidden behind obfuscated defined-name flow.
  • 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.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

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) 78076 bytes
SHA-256: 56b76f70941b6aa940de95c15f131401e17841148d8f3483127426a86536815a
Preview script
First 1,000 lines of the extracted script
' 0085     10 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  o
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet
' 0085     27 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  hGyuGXlHuFcXBCiDIQ
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet
' 0085     15 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet1
' 0085     15 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet1
' 0085     15 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet1
' 0085     15 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet1
' 0085     15 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet1
' 0085     15 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet1
' 0085     15 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet1
' 0085     15 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet1
' 0085     15 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet1
' 0085     15 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet1
' 0085     15 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet2
' 0085     15 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet2
' 0085     15 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet2
' 0085     15 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet2
' 0085     15 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet2
' 0085     15 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet2
' 0085     15 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet2
' 0085     15 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet2
' 0085     15 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet2
' 0085     15 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet2
' 0085     15 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet3
' 0085     15 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet3
' 0085     15 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet3
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0018     31 LABEL : Cell Value, String Constant - ajHCfhOUnvlRMMLQ len=0 
' 0018     53 LABEL : Cell Value, String Constant - aKUaWizBWXgElPeLRksiOJKINxqxcDoFILDcFj len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  o!DU53916 
' 0018     41 LABEL : Cell Value, String Constant - bhBJxdZZYcOUcsTSiYbTrVzxfU len=0 
' 0018     59 LABEL : Cell Value, String Constant - bIlBhoHPFkfgejVOVyaLbfiZybHqmbvlcqBjjWJjGThP len=0 
' 0018     38 LABEL : Cell Value, String Constant - BIPfGGVLOGeImkSHbSJWgQP len=0 
' 0018     46 LABEL : Cell Value, String Constant - BKFixRkEynTcdbgRLSvJIYcfWvLDnVX len=0 
' 0018     23 LABEL : Cell Value, String Constant - BsRgZJrt len=0 
' 0018     58 LABEL : Cell Value, String Constant - BuNKhDbTQbsHcQZxrVXEYdlbHQQPUqxFjwvMPSKixqa len=0 
' 0018     37 LABEL : Cell Value, String Constant - BuNKhDbUQbsHcQaxsWXEYd len=0 
' 0018     46 LABEL : Cell Value, String Constant - bVnXtdntpCThpqzXSvxekEMChcdbgRY len=0 
' 0018     21 LABEL : Cell Value, String Constant - CbCNHZ len=0 
' 0018     20 LABEL : Cell Value, String Co
... (truncated)