Malicious PDF — malware analysis report

Static analysis result for SHA-256 fbf9735b6258dad4…

MALICIOUS

PDF

82.5 KB Created: 2021-09-09 12:54:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 2d6b12cd030a2f3b576d4e02d5890901 SHA-1: 8ad836db989f94bfde8f6c886b2f5191dba0a7a3 SHA-256: fbf9735b6258dad4860dc88c8a5eed25fdbbe53315cc3af269924daca00cbed0
156 Risk Score

Malware Insights

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

The PDF contains a link farm pointing to numerous other PDF files, many hosted on domains flagged as potentially compromised or disposable. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or malware distribution. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather as a container for these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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 https://hongmao.tw/uploads/files/202109061632337035.pdf In PDF document text
    • http://asustainable.com/global/file/lijilotubimusuje.pdfIn PDF document text
    • https://rijst.nu/userfiles/file/9274432788.pdfIn PDF document text
    • http://christopherdallo.com/file/75310162952.pdfIn PDF document text
    • http://realtor-madrid.com/uploades/fckeditorfile/pudofebenul.pdfIn PDF document text
    • http://orderkai.com/uploads/files/janokubutipobafininisali.pdfIn PDF document text
    • https://indianhairtransplant.com/ckfinder/userfiles/files/3670362296.pdfIn PDF document text
    • http://popnmusic.fr/userfiles/file/64007257804.pdfIn PDF document text
    • https://cashofferoregon.com/wp-content/plugins/formcraft/file-upload/server/content/files/16133dc2409d3b---35451565635.pdfIn PDF document text
    • http://actlogistic.vn/upload/editor/files/kiziw.pdfIn PDF document text
    • http://beautifulmoda.com/userfiles/files/6013670001.pdfIn PDF document text
    • https://essuances.com/ckfinder/userfiles/files/42037922511.pdfIn PDF document text
    • https://www.hotelrestaurantmacarena.fr/ckfinder/userfiles/files/99091786415.pdfIn PDF document text
    • http://aquatherm-graz.at/files/69250732497.pdfIn PDF document text
    • http://webinaris.eu/ckfinder/userfiles/publics/files/15071110383.pdfIn PDF document text
    • http://asesoriagarpe.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139653311695---ratefiwukuwudim.pdfIn PDF document text
    • http://hamlineparkplaza.com/assets/amund/ckfinder/userfiles/files/72208671758.pdfIn PDF document text
    • http://leicesterbiketec.com/userfiles/file/58013600946.pdfIn PDF document text
    • http://www.enjoyvaltellina.it/admin/ckfinder/userfiles/files/68102388278.pdfIn PDF document text
    • http://erago.cidees.com/uploads/files/nibosaki.pdfIn PDF document text
    • http://kyochonbuenapark.iorderfoods.com/uploads/files/xewifewijoku.pdfIn PDF document text
    • http://www.bewegeninarnhem.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1613961bc5f4a2---penesapesenemikesuwodoliz.pdfIn PDF document text
    • http://mmbc.cz/_data/user_files/file/dinefitita.pdfIn PDF document text
    • https://www.oalysa.cz/ckfinder/userfiles/files/26790430123.pdfIn PDF document text
    • https://aluminiosarla.com/userfiles_arla/files/63826600360.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/DOqCt-cVA4I/uplcv?utm_term=running+man+most+popular+episodePDF 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_off0000dadb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDADB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f2f2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2F2 10880 bytes
SHA-256: 92cf3d075374096e29978225a0a0e83c31afb08eb4862a8b6422b8560ae72766
font_02_sfnt_off00010bde.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10BDE 18704 bytes
SHA-256: 60647c9a681764b4d9ca96eb6f8f7d67188d29ce216af2244a914a3468d9df2b