Malicious PDF — malware analysis report

Static analysis result for SHA-256 638efd8f0a02f86b…

MALICIOUS

PDF

80.9 KB Created: 2021-09-07 21:50:03 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 6773c0cf70336e02454055ceb1502081 SHA-1: 1cf98a16fbd80ba6cedf04e5059f1d813260be4b SHA-256: 638efd8f0a02f86b15cc23e885244e4a7e0696e23a95c7bf616e4e5a2365984d
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains numerous links, many pointing to compromised WordPress sites and disposable domains, indicating a link farm designed to lure users to potentially malicious content. The ML classifier and ClamAV detection strongly support its malicious nature. No scripts were extracted, but the structure and URL analysis are sufficient to determine the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://okmarin.ru/userfiles/file/nimovusavanebik.pdf In PDF document text
    • https://martybermanassociates.com/wp-content/plugins/super-forms/uploads/php/files/200907c43e679df8c40c5a1e4f361238/55117890831.pdfIn PDF document text
    • https://brylka-kfz.de/wp-content/plugins/formcraft/file-upload/server/content/files/160a28deb8f734---digani.pdfIn PDF document text
    • https://connatlas.com/home/conn/public_html/ckfinder/userfiles/files/94278368796.pdfIn PDF document text
    • http://www.kevinbrooks.ca/wp-content/plugins/formcraft/file-upload/server/content/files/16085867be8530---regowimupugexu.pdfIn PDF document text
    • http://eduomania.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d82146cbc5f---gixovosemusefara.pdfIn PDF document text
    • http://bioterapiazabiegi.pl/obrazy/file/50313754317.pdfIn PDF document text
    • http://jncs.kr/page_data/file/20210622194145.pdfIn PDF document text
    • http://bridgesonthepark.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d2637cf1d9a---kotozed.pdfIn PDF document text
    • https://swotin.com/wp-content/plugins/formcraft/file-upload/server/content/files/1611d8066584ac---49728772723.pdfIn PDF document text
    • https://www.rockandroll.blog.br/wp-content/plugins/super-forms/uploads/php/files/onsvracddggelalpiprdt1ktbj/puvonaf.pdfIn PDF document text
    • https://nutstudio.it/userfiles/file/88386602016.pdfIn PDF document text
    • https://nutrishop.in/ci/userfiles/files/xukaruduze.pdfIn PDF document text
    • http://rymwid-training.com/userfiles/file/mulix.pdfIn PDF document text
    • https://www.web2business.pt/wp-content/plugins/formcraft/file-upload/server/content/files/160c9a0f8543f0---62649773438.pdfIn PDF document text
    • https://www.diktu.com/wp-content/plugins/formcraft/file-upload/server/content/files/16102d068a03c7---bizizivugatifaxoj.pdfIn PDF document text
    • https://www.frankreich-ferien.ch/wp-content/plugins/formcraft/file-upload/server/content/files/1607e5f13b82fa---jemokubaxalevujova.pdfIn PDF document text
    • http://www.catedralirodahaz.hu/data/editorfile/rifixileto.pdfIn PDF document text
    • http://braintradingbcn.com/wp-content/plugins/super-forms/uploads/php/files/7a505ac0758e70fea7bb692187ee0f70/rawogawudimakedilotejotaz.pdfIn PDF document text
    • http://hyunshin.net/userfiles/file/madik.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/ngfLrbzwjls/uplcv?utm_term=zonare+z.one+pro+manualPDF 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_off0000d806.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD806 18192 bytes
SHA-256: 61b002339059dfb29ee99eb16da40a27d6aeb6284464cd650258e4ef8c2df62e
font_01_sfnt_off00010769.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10769 10244 bytes
SHA-256: 15f423d4fe48a0955999fca55af4643660c69fe00f548c683c04a93ede67ac09
font_02_sfnt_off00011e62.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E62 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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