Malicious PDF — malware analysis report

Static analysis result for SHA-256 5b3bbd5e6aea3f1e…

MALICIOUS

PDF

75.9 KB Created: 2021-09-17 00:11:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: daf14b563c5ddcffbd59363a180c2e69 SHA-1: 911dbf286fc046b877e2c2869f4f9cebe7ddfefe SHA-256: 5b3bbd5e6aea3f1e5f5fcf9d1c234cdc7b94e87d42c67fd7e17ffbf35c587886
156 Risk Score

Malware Insights

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

The file is identified as malicious by ClamAV and an ML classifier. Heuristics indicate it functions as a link farm, directing users to multiple external URLs, some hosted on compromised CMS platforms. The document body is heavily obfuscated and unreadable, suggesting it's designed to obscure its malicious intent rather than convey information.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

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://www.kiteschule-kiel.de/wp-content/plugins/formcraft/file-upload/server/content/files/16135fbb78937f---58900994510.pdf In PDF document text
    • http://www.saraviation.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613f195b4c39d---9642622219.pdfIn PDF document text
    • https://zenithoverseas.com/assets/userfiles/files/rezovamu.pdfIn PDF document text
    • https://refundsrefunds.com/wp-content/plugins/formcraft/file-upload/server/content/files/16136bec06dd4c---72009130863.pdfIn PDF document text
    • http://studioriboldi.eu/userfiles/files/jobibolijitok.pdfIn PDF document text
    • http://studiosiriosrl.it/userfiles/files/womirekud.pdfIn PDF document text
    • http://letresorellebio.it/userfiles/files/gemaxufaxomebu.pdfIn PDF document text
    • https://braintreeclinics.com/app/webroot/img/files/wurumeripalo.pdfIn PDF document text
    • http://www.hgekc.com/media/userfiles/file/5122904330.pdfIn PDF document text
    • http://rickgrisolia.com/userfiles/files/75731457322.pdfIn PDF document text
    • http://kortennis.co.kr/B/ck/ckfinder/userfiles/files/76150693521.pdfIn PDF document text
    • http://velapower.com/glwh/UploadFile/file/2021090411361873499.pdfIn PDF document text
    • http://www.bongbansaigon.com/uploads/files/mibasujalupumorazagulebil.pdfIn PDF document text
    • http://rovitek.com/userfiles/file/50723660234.pdfIn PDF document text
    • http://twtqedu.com/userData/ebizro_board/file/79298435874.pdfIn PDF document text
    • https://cokhivietuc.com/img-vietuc/files/9751609265.pdfIn PDF document text
    • http://vakoplus.cz/klienti/devel/sneznerolby.cz/ckfinder/userfiles/files/kafubilukupawa.pdfIn PDF document text
    • https://grancom.by/upload/docs/rojuxaxapojolekej.pdfIn PDF document text
    • http://mbjarrahi.com/UploadedFiles/New/file/91518809012.pdfIn PDF document text
    • http://winfielddeli.com/ckfinder/userfiles/files/73504664901.pdfIn PDF document text
    • http://lycee-elm.org/userfiles/file/32940334466.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/zMnd8XtcwSM/uplcv?utm_term=haruki+murakami+short+stories+pdfPDF link annotation
    • https://www.thc.gda.pl/ckfinder/userfiles/files/novatudewozeripejovug.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_off0000c218.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC218 18112 bytes
SHA-256: 47ebca54e628500264ffc98338a34883312b09dc50bdd609bbc5f339f92e3feb
font_01_sfnt_off0000f0ec.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF0EC 10796 bytes
SHA-256: 69b61185384333b74bba40fb977cb98603bb2634c6540a5c632888d4361d1d76
font_02_sfnt_off000109cb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x109CB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1