Malicious PDF — malware analysis report

Static analysis result for SHA-256 8f633f38479e36a3…

MALICIOUS

PDF

86.0 KB Created: 2021-09-02 17:59:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: edb8726cc3cc00283455af4bc7731b6c SHA-1: a7e06807cf18fe875b939e594bef7354f124911c SHA-256: 8f633f38479e36a31a6b4c46cf082e868af533d7066dd80d94d08d440161860a
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is identified as malicious by ClamAV and an ML classifier. It functions as a link farm, containing numerous URLs pointing to PDF files hosted on various domains, some of which appear to be compromised. The presence of PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics indicates a pattern of using link farms for SEO manipulation or to distribute malicious content. While no scripts were directly extracted, the nature of PDF link farms often involves embedded JavaScript to facilitate redirects.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9848

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://fmafirm.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/terotaxoxalijizor.pdf In PDF document text
    • https://bursakaynak.com/userfiles/file/zubegofowuw.pdfIn PDF document text
    • http://fusheng-vietnam.vn/admin/webroot/upload/image/files/panuwidebujo.pdfIn PDF document text
    • http://taxplus.in/images/contentimages/files/dogafamulabatuxi.pdfIn PDF document text
    • https://kovtec.pl/eurostyl/photos/file/74900054810.pdfIn PDF document text
    • http://aberdeeneyes.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1608796edda4fe---lebapovanirojekafix.pdfIn PDF document text
    • https://mehreganimaging.com/images/upload/files/22778922873.pdfIn PDF document text
    • http://bmcnx.com/userfiles/file/tawidavapex.pdfIn PDF document text
    • https://www.aserspa.net/wp-content/plugins/super-forms/uploads/php/files/r6usqb10mmcjjb84828dqp19ga/61815851356.pdfIn PDF document text
    • http://satisfytech.com/ck/upload/files/purezuwawepo.pdfIn PDF document text
    • https://recapress.com/ckfinder/userfiles/files/fugamabusa.pdfIn PDF document text
    • https://5a.ro/ckfinder/userfiles/files/vomawotusasexezedes.pdfIn PDF document text
    • http://www.vitrierbxl.be/wp-content/plugins/formcraft/file-upload/server/content/files/160a3b0d509adb---60747719754.pdfIn PDF document text
    • http://jshtextile.com/UserFiles/file///xutodizerebuwabo.pdfIn PDF document text
    • https://staffxrecruitment.com/wp-content/plugins/super-forms/uploads/php/files/9d80c7eb8f8da5be8f747a1b2a7d9be0/50935565080.pdfIn PDF document text
    • http://jar-ted.pl/file/40000452622.pdfIn PDF document text
    • https://metroguards.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160d483efe6252---feketepimujarixozadedul.pdfIn PDF document text
    • http://aarogyamedico.com/userfiles/file/37617525790.pdfIn PDF document text
    • https://nuregio.de/wp-content/plugins/formcraft/file-upload/server/content/files/160c6f3bf1d8eb---mitemofejonixenukinejife.pdfIn PDF document text
    • https://europeancustomtailor.com/wp-content/plugins/super-forms/uploads/php/files/64c0c18b1beccbb70a9418008e95c0de/vusodexumotejixofeledotom.pdfIn PDF document text
    • http://markfarolaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/jexawovune.pdfIn PDF document text
    • http://clinicaveterinariabilancino.it/userfiles/files/25032414633.pdfIn PDF document text
    • https://weyergans-hcc.lv/userfiles/file/75708942337.pdfIn PDF document text
    • http://ventilyatsia-v-sochi.ru/ckfinder/userfiles/files/jopizubatokiritotonopef.pdfIn PDF document text
    • http://merwepizza.com/upload/file/xitupuvatidav.pdfIn PDF document text
    • http://wakingbeauty.com/wp-content/plugins/formcraft/file-upload/server/content/files/16079824a17e9f---xusibudab.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=cell+phone+schematic+diagram+pdfPDF 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_off0000e9af.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE9AF 11096 bytes
SHA-256: 59bd36cb3dea301cfe50c59b3b7419663f0f420b2e8b3f9fe4ea1914144551a8
font_01_sfnt_off00010326.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10326 18040 bytes
SHA-256: 9e84e9371f2f187e2cc43ec48a3ef46439f57389b047d2c0c47f4b60dd78eb64
font_02_sfnt_off00013271.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13271 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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