Malicious PDF — malware analysis report

Static analysis result for SHA-256 4dadaeb87afe2762…

MALICIOUS

PDF

78.4 KB Created: 2021-09-16 14:14:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: d7bb8c70dd63b57a221a7c7be3ff409b SHA-1: 98fa7f2caa67223237203287d261e5e7cfc94a13 SHA-256: 4dadaeb87afe276238ece3dd445b346f1e1cfb33c938b77c7dfdaa604da1eaba
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file that contains numerous links to external websites, many of which are hosted on compromised WordPress sites or disposable domains. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The presence of PDF_RANDOM_URL_LINK and PDF_SEO_DISPOSABLE_LINK_FARM heuristics suggests an attempt to obscure the final malicious destination.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 7

  • 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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://inwebjor.ru/uplcv?utm_term=4+hour+superhero+movie PDF link annotation
    • http://enslev-anlaegsservice.dk/userfiles/file/wunuwuxiwigenugobir.pdfIn PDF document text
    • https://samoinstitute.mn/uploads/assets/file/zazibefijuxowilazuku.pdfIn PDF document text
    • https://kawanmto.net/contents/files/9067509555.pdfIn PDF document text
    • https://wickedcheesy.com/images/file/gerekelowarijimalopifom.pdfIn PDF document text
    • http://niengrangchuyensau.com/upload/contentFile/file/bopepu.pdfIn PDF document text
    • http://k12kos.com/ckfinder/userfiles/files/13149252900.pdfIn PDF document text
    • https://www.bountyvacation.com/wp-content/plugins/formcraft/file-upload/server/content/files/161370bc74b238---1720237999.pdfIn PDF document text
    • http://www.timtransportes.com/home/wp-content/plugins/formcraft/file-upload/server/content/files/161413c959969c---salinotuvazafikekagezokot.pdfIn PDF document text
    • https://lentes123.com/aym_image/files/puletoj.pdfIn PDF document text
    • http://zatoodesign.com/userfiles/files/wawatodupemilep.pdfIn PDF document text
    • https://cuatudongnhatrang.com/uploads/files/kugigokeziboluto.pdfIn PDF document text
    • https://tlproduct.com/userfiles/file/23736364935.pdfIn PDF document text
    • http://www.trisad.kz/ckfinder/userfiles/files/80024972204.pdfIn PDF document text
    • http://nsk-nalogov.net/upload/files/78685543200.pdfIn PDF document text
    • http://reanda.com/jingkelun/userfiles/files/20210912125108.pdfIn PDF document text
    • https://apexforestservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/16131a3213fa6f---22954964205.pdfIn PDF document text
    • http://firmykominkowe.pl/Obrazki/edytor/file/33268199673.pdfIn PDF document text
    • http://xn--2-140-swe8h.xn--p1ai/files/21617578305.pdfIn PDF document text
    • http://www.mondzorgvesa-voorschoten.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1613ba779614aa---54262205039.pdfIn PDF document text
    • http://teleinwestor.com/userfiles/file/nawuropofoja.pdfIn PDF document text
    • http://ambulatorioveterinariovianello.eu/userfiles/files/26515525028.pdfIn PDF document text
    • https://alcoquimicos.com/ckfinder/userfiles/files/jegusakefopu.pdfIn PDF document text
    • http://www.premiumimport.nl/ckfinder/userfiles/files/reranog.pdfIn PDF document text
    • https://hoovermaids.com/wp-content/plugins/super-forms/uploads/php/files/c2890bccaa4a40a0cde1dde032acceea/38982609947.pdfIn PDF document text
    • http://parentini.it/userfiles/files/motala.pdfIn PDF document text
    • 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_off0000cdc1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCDC1 10252 bytes
SHA-256: e395bf090d78ce9d7bfbbe24dcad2fb5b971a5c2ae393d9024d26e7502f81893
font_01_sfnt_off0000e4db.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE4DB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000fced.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFCED 18028 bytes
SHA-256: 3efcd0a45411d23a26b54d40e3f537ecc3b16e25384cf18159651489ac4f7880