Malicious PDF — malware analysis report

Static analysis result for SHA-256 431a8326bb63ae7c…

MALICIOUS

PDF

77.7 KB Created: 2021-09-08 09:58:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: c5c1508eed4bd7c406d752415d78426c SHA-1: f5c7f595aac9ef51aa264d2e642801d435353185 SHA-256: 431a8326bb63ae7cdf01fcc6133a056f96891e3d6cae9cbeeb42384a85d7c9f2
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was detected as malicious by ML classifiers and ClamAV, indicating a phishing or trojan threat. It contains numerous links to external websites, many hosted on compromised CMS uploads, suggesting a link farm designed to redirect users to malicious content. The presence of embedded URLs and the nature of the heuristics point towards an attempt to exploit users through deceptive links, likely as part of a phishing campaign or to download further malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

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://www.colegiometa.net/home/wp-content/plugins/formcraft/file-upload/server/content/files/1608d1393976dc---dazuzezexowev.pdf In PDF document text
    • http://anhuifan.com/upload_fck/file/2021-8-23/20210823175142162497.pdfIn PDF document text
    • http://blueyee.com/upload/file/141122177690.pdfIn PDF document text
    • https://umartravel.com/files/ziram.pdfIn PDF document text
    • http://ferrocom-spb.ru/userfiles/files/tixafivupinibo.pdfIn PDF document text
    • https://study4student.com/cache/fck_files/file/2679988761.pdfIn PDF document text
    • http://schokobrunnen.com/idata/38245252163.pdfIn PDF document text
    • http://dalnoboy.net/data/filestorage/upload/files/75909780864.pdfIn PDF document text
    • https://dacoma.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160f0f06aba0fc---divanobuwe.pdfIn PDF document text
    • https://best-turbos.com/wp-content/plugins/super-forms/uploads/php/files/b851ec1dedd15f9df93393f3cb51cb70/vadoporagexobip.pdfIn PDF document text
    • https://moto-trend.cz/public/files/fck/file/fafik.pdfIn PDF document text
    • http://insidethedigitaltrend.biz/userfiles/file/minutafinojow.pdfIn PDF document text
    • https://profbuhotchet.ru/wp-content/plugins/super-forms/uploads/php/files/f5a309bf37955d229dad5a7afcd8be2d/85915675203.pdfIn PDF document text
    • http://www.cheapmotorcycleinsurancepa.com/wp-content/plugins/super-forms/uploads/php/files/pndbhsomaq92opr0rau41kujb2/nikajogokevenoribivujokuz.pdfIn PDF document text
    • https://www.americanapi.com/wp-content/plugins/formcraft/file-upload/server/content/files/160db19b4abf36---31769272027.pdfIn PDF document text
    • http://springswellness.net/wp-content/plugins/formcraft/file-upload/server/content/files/160a7c17c0a815---6045096328.pdfIn PDF document text
    • http://sarljarry.fr/userfiles/file/losujoxujuratojux.pdfIn PDF document text
    • https://sieuthimaytinhcu.vn/upload/files/ketegovi.pdfIn PDF document text
    • https://aristi-trap.com/upload/users/files/33382318540.pdfIn PDF document text
    • http://zadonskiy.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1609f7d69087b8---15924479730.pdfIn PDF document text
    • https://ludifrance.fr/userfiles/file/jusagubitaxuruj.pdfIn PDF document text
    • https://lakeshoresmilesdentistry.com/wp-content/plugins/super-forms/uploads/php/files/ph8qkmamir47cso9kp2tjqpam5/kuvaxumubitexozog.pdfIn PDF document text
    • https://trsoftyazilim.com/genelresimler/file/jusapukekit.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/DOqCt-cVA4I/uplcv?utm_term=application+layer+in+cn+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_off0000cc90.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCC90 10540 bytes
SHA-256: a6868c1a9f799ea996a45d0d259486eaef44fa23eb4090ae023ffb735054e471
font_01_sfnt_off0000e4c3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE4C3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000fcd5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFCD5 17040 bytes
SHA-256: 49816b890bf2baacc6f8a896c376917c20f95903c1feac502d46b913b570ab98

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