Malicious PDF — malware analysis report

Static analysis result for SHA-256 8b80fd6dbd8f3835…

MALICIOUS

PDF

77.7 KB Created: 2021-09-14 02:33:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: c37455531b6a7598de8f9bc7dbb10b4f SHA-1: 77bddf9e5b112916c19590ce7d292aead583ad53 SHA-256: 8b80fd6dbd8f3835ddfbfe817a2da2613504a91e0b673b432d0b8c1eff0153d7
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised websites or disposable hosting, suggesting a link farm designed to redirect users to malicious content. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or malware delivery. The presence of external URI heuristics and compromised CMS upload links further supports this assessment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9963

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://e-uchebnici.com/img/file/darifewe.pdf In PDF document text
    • http://www.gamylai.vn/uploads/files/79678366260.pdfIn PDF document text
    • http://discarga.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613fd8d9066c2---98602782928.pdfIn PDF document text
    • http://geology.ie/wp-content/plugins/formcraft/file-upload/server/content/files/161386b26b1df0---tipafufon.pdfIn PDF document text
    • https://wisestudentz.com/userfiles/file/7122924165.pdfIn PDF document text
    • https://samsungdvmklima.com/upload/ckfinder/files/tibedojapewuvatawimuf.pdfIn PDF document text
    • http://dh-cell.net/ckfinder/userfiles/files/meligebesa.pdfIn PDF document text
    • http://hla.vn/upload/files/lasimefovenimevirux.pdfIn PDF document text
    • http://spadhotel.com/basefile/spadhotelcom/files/pekexu.pdfIn PDF document text
    • https://microfocus-realize2020mea.com/wp-content/plugins/super-forms/uploads/php/files/18f511d1a4a1e5bf42153c6261252483/tulajatimelabodipojenobot.pdfIn PDF document text
    • http://mamnonkitty.com/webroot/img/posts/files/wowopijorisobidavogugedol.pdfIn PDF document text
    • http://urbanconstructions.org/images/uploadedimages/file/musumemijekiselapavu.pdfIn PDF document text
    • https://jager-ig.tw/up_photo/file/duxofoseson.pdfIn PDF document text
    • http://miraesusan.com/ckupload/files/52625542545.pdfIn PDF document text
    • https://doan295doson.vn/namthuan/images/news/files/gowazogusavuginorikidov.pdfIn PDF document text
    • http://szkolaprzybranowo.pl/ckfinder/userfiles/files/23589606713.pdfIn PDF document text
    • http://pincailight.com/zk/UploadFile/file/2021090507495573499.pdfIn PDF document text
    • https://doctornhospital.com/banglanews24/editorsfiles/files/mutur.pdfIn PDF document text
    • https://cityface.cz/res/file/setagawam.pdfIn PDF document text
    • http://dj-maily.com/uploads/pages/files/nekudedinaf.pdfIn PDF document text
    • https://wodepcb.cn/uploadfiles/files/vuvute.pdfIn PDF document text
    • http://xn--80aaaaaikdebj9ccf1ayja1b5a3q.xn--p1ai/ckfinder/userfiles/files/sigexamosifewosekamuv.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BkSY9tpko7c/uplcv?utm_term=lara+croft+relic+run+modPDF 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_off0000ccc7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCCC7 17364 bytes
SHA-256: fa783f897ba0293101181c1295a8054c754610565f58cd2aac401d530793d537
font_01_sfnt_off0000f9c1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF9C1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000111d8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x111D8 10528 bytes
SHA-256: 0b040c5fab77324cfc2a8def1eda3b01c8c622114e4a69e9c2fc18a66f523fde