Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 2d208ca4bd3909d3…

MALICIOUS

Office (OLE)

123.0 KB Created: 2020-07-08 07:27:00 Authoring application: Microsoft Excel First seen: 2020-07-24
MD5: 61b9c31208fb2206f209d2e79e718919 SHA-1: 4d0940d7e3d92e6c63ded13cc3926e2ea1613bdc SHA-256: 2d208ca4bd3909d3fdf4357f7f95802411beaf693b5da247fdc06a0574b23989
260 Risk Score

Malware Insights

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

The file contains Excel 4.0 (XLM) macros, specifically an Auto_Open function, which is a critical finding. Heuristics indicate the presence of dangerous formula APIs and environment evasion techniques within the macro. ClamAV detection further confirms its malicious nature as 'Xls.Dropper.Agent-8900948-0'. The Auto_Open macro is designed to execute arbitrary commands, commonly used to download and execute further stages of malware.

Heuristics 5

  • ClamAV: Xls.Dropper.Agent-8900948-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.Agent-8900948-0
  • 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.

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) 72928 bytes
SHA-256: 1ccc170056dd00e34155105013d993903d4f1a746b9a64835c2bb8cf90053e6b
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 -  RnmOvNyD
' 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     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet
' 0085     15 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet1
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0018     22 LABEL : Cell Value, String Constant - aehYxNG len=0 
' 0018     50 LABEL : Cell Value, String Constant - afndJRSQVszHkxwNRULkzscKNhKOcYHVuuV len=0 
' 0018     52 LABEL : Cell Value, String Constant - aqtwoNcVFnpKmrFPkxlXyVUvdugkLlwqJGcxW len=0 
' 0018     34 LABEL : Cell Value, String Constant - aQvqrpufmtKkkzqskKm len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  !IE54488 
' 0018     43 LABEL : Cell Value, String Constant - BbmgyvSoNFBNesOCLidHJpKPXNsC len=0 
' 0018     53 LABEL : Cell Value, String Constant - bmETablJEhjPWpwmSNOMRDJQhIHXNQIgJomUJd len=0 
' 0018     49 LABEL : Cell Value, String Constant - bmVUItVrESzRDHhVTNfcyVtyvHKZuvFPKn len=0 
' 0018     22 LABEL : Cell Value, String Constant - BxsKIeO len=0 
' 0018     35 LABEL : Cell Value, String Constant - cHiTjnphHjOyuiDtkyJr len=0 
' 0018     21 LABEL : Cell Value, String Constant - CmfmRe len=0 
' 0018     20 LABEL : Cell Value, String Constant - cMtwR len=0 
' 0018     63 LABEL : Cell Value, String Constant - CMuuhUuResZrdhHvsmFCYuTZVgjyUVfojNdvQjdTyHIGLwpw len=0 
' 0018     21 LABEL : Cell Value, String Constant - CxlHwn len=0 
' 0018     25 LABEL : Cell Value, String Constant - cyisyuHXYt len=0 
' 0018     38 LABEL : Cell Value, String Constant - CzFcjqVhhwBEvUjcMtwRtxM len=0 
' 0018     21 LABEL : Cell Value, String Constant - DgwdjD len=0 
' 0018     39 LABEL : Cell Value, String Constant - dgXwZFCkYtjaoyhhUUvERsNr len=0 
' 0018     24 LABEL : Cell Value, String Constant - DirrqvSZg len=0 
' 0018     26 LABEL : Cell Value, String Constant - DJFQhiEFPmT len=0 
' 0018     21 LABEL : Cell Value, String Constant - dqeQrO len=0 
' 0018     24 LABEL : Cell Value, String Constant - dTytusxip len=0 
' 0018     18 LABEL : Cell Value, String Constant - dUh len=0 
' 0018     39 LABEL : Cell Value, String Constant - DWpJEsYhiglWPXBONdhjbBQI len=0 
' 0018     23 LABEL : Cell Value, String Constant - eEgLvrfB len=0 
' 0018     24 LABEL : Cell Value, String Constant - EfCBcKbNR len=0 
' 0018     57 LABEL : Cell Value, String Constant - EfnBcvbzRrRcWoYuepvrDUiqrCZUxyfmFNDidechSZ len=0 
' 0018     22 LABEL : Cell Value, String Constant - efpytXm len=0 
' 0018     50 LABEL : Cell Value, String Constant - EGaDIVfBOCnPlkMtLwBbBMGYWsOmfbmESnb len=0 
' 0018     56 LABEL : Cell Value, String Constant - EgkyuerRRsBNpJoMeEepjClIrDIFQhvEFOmgKMsyS len=0 
' 0018     22 LABEL : Cell Value, String Constant - enMsWlS len=0 
' 0018     61 LABEL : Cell Value, String Constant - eqTmSpIhITNfPlVflhtLZhirPKnpWcvEtZUVTYJQXnOOdT len=0 
' 0018     22 LABEL : Cell Value, String Constant - ETmHZUJ len=0 
' 0018     22 LABEL : Cell Value, String Constant - EUuuKBD len=0 
' 0018     28 LABEL : Cell Value, String Constant - FaclvqTjCWpjZ len=0 
' 0018     22 LABEL : Cell Value, String Constant - FdjfqtJ len=0 
' 0018     54 LABEL : Cell Value, String Constant - FFEJfmtYlkBEHyXmfPwzUwBPMuIhhJRdGZFduUu len=0 
' 0018     51 LABEL : Cell Value, String Constant - fnoyWRuvcjCKzfabZePWdtVUkadUtWCyhVqg len=0 
' 0018     55 LABEL : Cell Value, String Constant - FOONSDvDhutKNQ
... (truncated)

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