Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 911cb9fd746ece67…

MALICIOUS

Office (OLE)

178.0 KB Created: 2020-07-14 03:33:56 Authoring application: Microsoft Excel First seen: 2020-09-07
MD5: 9ef2317df117717c6a2c38bf8f756685 SHA-1: a5b42785846fe03005fc0ce65ea8e445aeb4fa4e SHA-256: 911cb9fd746ece672b220ed0d916a6f25396ed4f6ac6d703a81a0f0d4841caea
280 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open function, which is a known technique for executing malicious code. Heuristics indicate the use of dangerous API functions and environment evasion, suggesting a dropper functionality. ClamAV detection further confirms its malicious nature as Xls.Dropper.Agent-8840291-0.

Heuristics 6

  • ClamAV: Xls.Dropper.Agent-8840291-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.Agent-8840291-0
  • 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) 59665 bytes
SHA-256: be61f26c807783924a0951668c746e41a691afcfc2adf58dec3105dfcdaf8f01
Preview script
First 1,000 lines of the extracted script
' 0085      9 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  
' 0085     17 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  usxjcjOo
' 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, visible -  Sheet
' 0018     51 LABEL : Cell Value, String Constant - aHNgoeKFFEJtmtYykBEHyXBfPLzULCPZJIvh len=0 
' 0018     23 LABEL : Cell Value, String Constant - aILfIMaW len=0 
' 0018     21 LABEL : Cell Value, String Constant - aJIviJ len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  !BL47449 
' 0018     28 LABEL : Cell Value, String Constant - avxHeLoFlrLTI len=0 
' 0018     45 LABEL : Cell Value, String Constant - bcafQJQuWHXbdVuXCmhWqhYmwfeSEf len=0 
' 0018     24 LABEL : Cell Value, String Constant - BfQMzULCQ len=0 
' 0018     27 LABEL : Cell Value, String Constant - BHDOfgCENkRu len=0 
' 0018     20 LABEL : Cell Value, String Constant - BKKJO len=0 
' 0018     23 LABEL : Cell Value, String Constant - brvxpPrW len=0 
' 0018     51 LABEL : Cell Value, String Constant - BuNKgDbTPbsHcQZwrVXEYdlbHQQOTqxFjvvL len=0 
' 0018     22 LABEL : Cell Value, String Constant - BVMDQbK len=0 
' 0018     59 LABEL : Cell Value, String Constant - BvvuzkdkPpbruxpOrWGCqLCsGQzymYzWiwevhlMzxrKH len=0 
' 0018     47 LABEL : Cell Value, String Constant - BXHSXUfwLTUdCwZbIOhpfLGHFKuCJZBz len=0 
' 0018     49 LABEL : Cell Value, String Constant - BXtSKGSixTHQniMOuOUcRwGHFKhnvZmlCG len=0 
' 0018     23 LABEL : Cell Value, String Constant - ccafRXev len=0 
' 0018     23 LABEL : Cell Value, String Constant - CcnhzjGp len=0 
' 0018     59 LABEL : Cell Value, String Constant - CKyeaaZePVdtUTjZcUsWBygVpfWkuddQRltHiChGXjXV len=0 
' 0018     29 LABEL : Cell Value, String Constant - COcKbOSrfdXpmJ len=0 
' 0018     20 LABEL : Cell Value, String Constant - CppRZ len=0 
' 0018     32 LABEL : Cell Value, String Constant - dbgELSvJIYcfWvLDn len=0 
' 0018     23 LABEL : Cell Value, String Constant - dcsvyqPe len=0 
' 0018     45 LABEL : Cell Value, String Constant - DDdmybuaxQpQbVnWtdntpCShoqzXSv len=0 
' 0018     34 LABEL : Cell Value, String Constant - dfMfltiOXYWbyFMqEDT len=0 
' 0018     46 LABEL : Cell Value, String Constant - DGxWleOvyTvzOLtHggIQcFYEbtTtFyR len=0 
' 0018     41 LABEL : Cell Value, String Constant - djfrIJegpNuXnUatCqWSSRWHzH len=0 
' 0018     31 LABEL : Cell Value, String Constant - DkCosSsExQNjGeWS len=0 
' 0018     63 LABEL : Cell Value, String Constant - doiBjHqBHDPfuCENkfJLrxRZOtppotelsJjiyorjIlQOvkFv len=0 
' 0018     23 LABEL : Cell Value, String Constant - dPIPtGGV len=0 
' 0018     25 LABEL : Cell Value, String Constant - dqdQqNMoWn len=0 
' 0018     64 LABEL : Cell Value, String Constant - dyXdZloEZajtoShzUniXDMNLQBtBfsrIMOGftmXFHbEJWhCPD len=0 
' 0018     35 LABEL : Cell Value, String Constant - DZlzhykoODztMJgCagco len=0 
' 0018     22 LABEL : Cell Value, String Constant - EawVNJV len=0 
' 0018     24 LABEL : Cell Value, String Constant - ehZxbGEla len=0 
' 0018     31 LABEL : Cell Value, String Constant - eJjVkorjIlQzvkFu len=0 
' 0018     26 LABEL : Cell Value, String Constant - eMdPTthfZro len=0 
' 0018     23 LABEL : Cell Value, String Constant - EPURctuQ len=0 
' 0018     25 LABEL : Cell Value, String Constant - esPQZjeIXp len=0 
' 0018     52 LABEL : Cell Value, String Constant - EulyJrrffGPbEXDasFspjCyWGQWSeuvRTczhL len=0 
' 0018     54 LABEL : Cell Value, String Constant - EVvuLBEvUxcaIwRHxMWFFrsTcoQkPnGRGDwPMjT len=0 
' 0018     22 LABEL : Cell Value, String Constant - eYqnKgF len=0 
' 0018     54 LABEL : Cell Value, String Constant - eYqnKtEKGSjkGHQnVyOuBUcSxstrwhahMmYorum
... (truncated)

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