Malicious PDF — malware analysis report

Static analysis result for SHA-256 b6d01ebb0662c257…

MALICIOUS

PDF

82.8 KB Created: 2021-09-20 05:06:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 803a3faa4d02adbbcc578124b6cf052a SHA-1: 8da0c6efb931dc86d1480063e385b0bdf6e27b9b SHA-256: b6d01ebb0662c25705c057cff7c1de1dad265d712643cfbe5bb973d0c654603d
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file was flagged by ML classifiers and ClamAV as malicious, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm, with many URLs pointing to potentially compromised WordPress upload directories and disposable hosting. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9982

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://www.deadclan.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1613a022e8edeb---rawil.pdf In PDF document text
    • http://viswinkelindex.nl/images/uploads/16900146465.pdfIn PDF document text
    • http://sun-green.be/ckfinder/userfiles/files/fivifu.pdfIn PDF document text
    • https://qigoodteam.com/uploads/files/202109040959434935.pdfIn PDF document text
    • http://www.ktgroup.co.uk/ckfinder/userfiles/files/faxajarojagimifowaxef.pdfIn PDF document text
    • http://old.bgk-meshkova.com/ckeditor/ckfinder/userfiles/files/57938411492.pdfIn PDF document text
    • https://nuevocoach.co.uk/wp-content/plugins/super-forms/uploads/php/files/741bc32a6c712adcb7ad967b471db245/93018583996.pdfIn PDF document text
    • http://conhantaoankhanh.com/webroot/img/files/5555503689.pdfIn PDF document text
    • https://nomaquito-travel.com/editor-images/699526516.pdfIn PDF document text
    • https://stvorki.ru/files/file/87339291811.pdfIn PDF document text
    • http://apsencollege.org/test/fckeditor/file/4544857644.pdfIn PDF document text
    • http://ytovietnam.net/ckfinder/userfiles/files/78522058458.pdfIn PDF document text
    • https://quangcaowebsite.xemlaco.com/uploads/files/segemutav.pdfIn PDF document text
    • https://phucatgarment.com.vn/ckfinder/userfiles/files/kudizosiwejisisu.pdfIn PDF document text
    • https://arizonapoolcontractor.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613f727bb1011---jezen.pdfIn PDF document text
    • http://bladensburg.abwingsmd.com/uploads/files/lunitukopiwikap.pdfIn PDF document text
    • https://ip-kamera-rendszer.nuttydog.hu/ckfinder/userfiles/files/76705528779.pdfIn PDF document text
    • https://pharma-tools.pl/galeria/file/52792847144.pdfIn PDF document text
    • https://queensflower.nl/clientfiles/gogolotod.pdfIn PDF document text
    • http://suarezbeltran.com/aym_images/files/60375785171.pdfIn PDF document text
    • http://compufoxmail.com/FCKeditor/editor/filemanager/connectors/userfiles/file/tixubebuno.pdfIn PDF document text
    • https://netcsemege.elelmiszer-hazhozszallitas.hu/ckfinder/userfiles/files/fujodewuxavopapivuzefil.pdfIn PDF document text
    • http://costanzolegal.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/51616196853.pdfIn PDF document text
    • http://k9careclinic.in/ckeditor/ckfinder/userfiles/files/jorakatebul.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/cv9VXjIrmdE/uplcv?utm_term=the+seven+deadly+sins+free+streamPDF link annotation
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000de71.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE71 17972 bytes
SHA-256: e2f37e1094b19c9525be7a1cea1907bd284a62e104bd6df0080baeff7e1b1c67
font_01_sfnt_off00010d1e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10D1E 10640 bytes
SHA-256: f4362de5b5206898f405318277171d71d34e16e6cb3486cf956c517233423115
font_02_sfnt_off0001254b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1254B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1