Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 fe484a6556303f87…

MALICIOUS

Office (OLE)

390.0 KB Created: 2020-07-10 10:41:45 Authoring application: Microsoft Excel First seen: 2020-09-07
MD5: 65856250d2d1d5b1c572d1bd858e3cbf SHA-1: f737f1506ad2777467a7bea4fef94a6bfc9df1fc SHA-256: fe484a6556303f87a453fe263cc98ad79e3265e17d7052680f427536d7d52e2b
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open function, which is a known method for executing malicious code. The critical heuristic 'OLE_XLM_DANGEROUS_FN' indicates the use of dangerous formula APIs, including 'RUN', suggesting the macro attempts to execute an external payload. The macro sheet itself is heavily obfuscated with numerous string constants, making detailed analysis difficult but reinforcing the 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) 104549 bytes
SHA-256: af6777d3e23874aaccac55a29e0edcac5ac209599bf81eb7c5d81f74b36f9fc6
Preview script
First 1,000 lines of the extracted script
' 0085     13 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, very hidden -  Erro
' 0085      9 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  
' 0085     16 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  VeriSig
' 0018     16 LABEL : Cell Value, String Constant - a len=0 
' 0018     55 LABEL : Cell Value, String Constant - aBmCGJBZDhRNCWMDRbKKwjLhtIpHswWLICURoKio len=0 
' 0018     48 LABEL : Cell Value, String Constant - akqmyPelnwUPsubhBJxeZZYdOVcsTSiYb len=0 
' 0018     33 LABEL : Cell Value, String Constant - aloEZaktoShBVniYEM len=0 
' 0018     42 LABEL : Cell Value, String Constant - aLsuQswLHpEcdENZCVzYqQqCvOw len=0 
' 0018     23 LABEL : Cell Value, String Constant - aOMGYVrN len=0 
' 0018     49 LABEL : Cell Value, String Constant - aUmkHqBHDPfgCENkSvLrxRZPupqoteXeJj len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Erro!HU12575 
' 0018     45 LABEL : Cell Value, String Constant - aVLqyzxDohoTfeuyCsShaKruPrvKUp len=0 
' 0018     21 LABEL : Cell Value, String Constant - aVyBhC len=0 
' 0018     42 LABEL : Cell Value, String Constant - awTrxtFIXstENIlBUoHCqXfgejU len=0 
' 0018     62 LABEL : Cell Value, String Constant - BaDhSOCWNEScLKxkLhtIpHtxXLJDVSoLjplwzPklvFzdsMg len=0 
' 0018     59 LABEL : Cell Value, String Constant - baqgjbzdIGncwmdrCkkXXyHUvQuTkwlicurPyJPLXnoK len=0 
' 0018     38 LABEL : Cell Value, String Constant - bgRKRvWIYbeWuYDniXriZmw len=0 
' 0018     31 LABEL : Cell Value, String Constant - bipGhgwmogGiNLth len=0 
' 0018     25 LABEL : Cell Value, String Constant - BKhcGIoJOW len=0 
' 0018     39 LABEL : Cell Value, String Constant - BkSVpSWkgPdDDdmybuaxQpQb len=0 
' 0018     34 LABEL : Cell Value, String Constant - bkwZsYvOaOLFXVrblrn len=0 
' 0018     27 LABEL : Cell Value, String Constant - BLGjyRlFyoUd len=0 
' 0018     22 LABEL : Cell Value, String Constant - blHUHtV len=0 
' 0018     24 LABEL : Cell Value, String Constant - blJEhiPjo len=0 
' 0018     19 LABEL : Cell Value, String Constant - BLUP len=0 
' 0018     31 LABEL : Cell Value, String Constant - blUUHHiqEfzeDUgV len=0 
' 0018     43 LABEL : Cell Value, String Constant - bnbZTliFozFCNefBCLjQtJpvPXNs len=0 
' 0018     42 LABEL : Cell Value, String Constant - BOCnPljMtLwBbBMGYVsOmfbmESn len=0 
' 0018     25 LABEL : Cell Value, String Constant - BPLuIhhJRd len=0 
' 0018     46 LABEL : Cell Value, String Constant - bsTsEyQzWGRXTevKSTdBvZaHOgoeKFG len=0 
' 0018     39 LABEL : Cell Value, String Constant - bTQbsHcQZxsVXEYdlbHQQPUq len=0 
' 0018     30 LABEL : Cell Value, String Constant - BxUEPURctuQRayf len=0 
' 0018     57 LABEL : Cell Value, String Constant - BxVqPIEPguQEOlgKLrMRZPuEEDIelsXkjzDGxWleOw len=0 
' 0018     41 LABEL : Cell Value, String Constant - bYHUttVdqSmRpHhITNfOlVflht len=0 
' 0018     57 LABEL : Cell Value, String Constant - byUskhsKYthqPKmoVpuDsYhhglIPWBONdgjbzPIrac len=0 
' 0018     62 LABEL : Cell Value, String Constant - CeubhBJxdZZYdOHOsTFVYbTrVzjfUofWjtccQCdzMaIZLPp len=0 
' 0018     62 LABEL : Cell Value, String Constant - cHFmbvmdqBjjXXxHTvPuSkwkhbtqOxIOKWmnJLUrZDSyFYg len=0 
' 0018     61 LABEL : Cell Value, String Constant - cieqtIefoytXmFZsmcIRSQVGyGkxwNQTLjyrcKMgJOblHU len=0 
' 0018     61 LABEL : Cell Value, String Constant - cjCKzfabZeQJQtVGWadUtWClhWqgXlveeREeBOcKbNRqfc len=0 
' 0018     47 LABEL : Cell Value, String Constant - cKyTKBOYIHuuVeqTmSpIUIGzSPlVflht len=0 
' 0018     55 LABEL : Cell Value, String Constant - cROIaXuQouqDGUprBLGiyRlFyoUddchSLSwKJZcf len=0 
' 0018     64 LABEL : Cell Value, String Constant - csUTjZbTsVzxgUpfWkuddQQrzNoInMdpdbVnkHqCIEPghDEOl len=0 
' 0018     23 LABEL : Cell Value, String Constant - ctfjKkvp len=0 
' 0018     51 LABEL : Cell Value, String Constant - ctGurlEBXHSYUfwxTVeCiMcJPiqfLHHGKvov len=0 
' 0018     24 LABEL : Cell Value, String Constant - curPkJPLX len=0 
' 0018     26 LABEL : Cell Value, String Constant - cUtJBlTVpSX len=0 
' 0018     17 LABEL : Cell Value, String Constant - CW len=0 
' 0018     44 LABEL : Cell Value, String Constant - CWpjZFOONSDvDh
... (truncated)

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