Malicious PDF — malware analysis report

Static analysis result for SHA-256 8b4c9cfcb48149e2…

MALICIOUS

PDF

74.5 KB Created: 2021-09-06 14:19:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: fcd9d63819984c8f939bc3fb3a9f5f52 SHA-1: 0c62ee8798b90ba3a18e1091f87a2695394566e2 SHA-256: 8b4c9cfcb48149e22fa74b0e9a3be2d9903cb29b5b61a0422500aeccb365f157
156 Risk Score

Malware Insights

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

The PDF document contains a large number of embedded URLs, many of which point to domains flagged as potentially compromised or disposable. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The document body is heavily obfuscated and unreadable, providing no direct user-facing content, but the heuristic firings confirm the link farm nature.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9939

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://www.alex-vasilkov.ru/images/wisdom/file/valezomobozutez.pdf In PDF document text
    • http://ahzycw.com/upload_fck/file/2021-9-2/20210902092328723463.pdfIn PDF document text
    • http://clinical-pain.com/pds/userfiles/files/telarapunadatobadoriramu.pdfIn PDF document text
    • https://expungemyrecordnj.com/wp-content/plugins/formcraft/file-upload/server/content/files/16103f3e88bc0c---nudokifuxar.pdfIn PDF document text
    • https://duocvinhkim.com/userfiles/file/13123912369.pdfIn PDF document text
    • https://lifecareproduct.in/ckfinder/userfiles/files/17533858212.pdfIn PDF document text
    • http://alhouti.com/userfiles/file/tafaferadabe.pdfIn PDF document text
    • https://www.saltriot.com/wp-content/plugins/super-forms/uploads/php/files/5d6e41d2ec4dcb1f10ff79b4d09f7820/66645677652.pdfIn PDF document text
    • https://alignerco.com/wp-content/plugins/super-forms/uploads/php/files/30fcbbb86a2f45edba45b9ae69a785af/novuzosugidepijuxoro.pdfIn PDF document text
    • https://promocionesnma.com/wp-content/plugins/super-forms/uploads/php/files/defa1ceb2c188bf93b1b0901483d366a/96541796818.pdfIn PDF document text
    • http://midlandhigh65.com/clients/6/68/682e31fde28f8c6bff7ebba57332ef5f/File/varibubaz.pdfIn PDF document text
    • http://k-yoga.org/file_upload/spaw_upload/file/20210626025325.pdfIn PDF document text
    • https://coopinproject.eu/ckfinder/userfiles/files/99715985234.pdfIn PDF document text
    • http://renovator.cz/files/file/vasopiwoni.pdfIn PDF document text
    • http://www.oschouston.com/osc/wp-content/plugins/formcraft/file-upload/server/content/files/16085df3fe1836---vefogemomepuridurike.pdfIn PDF document text
    • https://fcksa.com/ckfinder/userfiles/files/fopazizas.pdfIn PDF document text
    • http://fli.edu.mn/ckfinder/userfiles/files/figugejoxuzanuxodaga.pdfIn PDF document text
    • http://test.uebersetzungen-nesselberger.de/wp-content/plugins/formcraft/file-upload/server/content/files/160d06b0b94d83---viwakifil.pdfIn PDF document text
    • http://halmar.info/userfiles/file/71504261305.pdfIn PDF document text
    • http://livestreaming.group/wp-content/plugins/super-forms/uploads/php/files/kgo1tn41r26v3apdkv57ifd7095j9t29/tudesituzamej.pdfIn PDF document text
    • https://perfectprojects.ro/userfiles/file/zotibowa.pdfIn PDF document text
    • http://melabo.com/upload/files/49243993662.pdfIn PDF document text
    • http://kartelabasligi.com/images_upload/files/jutejupinikasalibesuwave.pdfIn PDF document text
    • http://hopkinshigh1988.com/clients/75739/File/vudugewexaviviruzazejaf.pdfIn PDF document text
    • https://sensesgrouphk.com/louis/STARKGROUP/ckfinder/userfiles/files/22087959454.pdfIn PDF document text
    • https://www.reflectionuk.com/wp-content/plugins/super-forms/uploads/php/files/j0r9k8ps99jkjra6il14s26b31/wumopuzuzilubuta.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1xuhb7AK25c/uplcv?utm_term=symfony+1.4+jobeet+tutorial+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_off0000bc94.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBC94 11248 bytes
SHA-256: f0503ff21f38dcedd6c88e6ee59ce91c13ff92564e720464e6c2ec2081a3fdd8
font_01_sfnt_off0000d6cf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD6CF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000eee1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEEE1 17436 bytes
SHA-256: 472cd4df63d16a8bc93e73dfaa7ef6ac8faede8c4a46ac6250c60a253776bf2f