Malicious PDF — malware analysis report

Static analysis result for SHA-256 f8c21bfddee376c6…

MALICIOUS

PDF

74.0 KB Created: 2021-06-22 17:12:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-27
MD5: 3ff92a05b3463f953c3c459de496fa55 SHA-1: 4311c5d7549ed93f8a6fd923a2efa92c84a31cd2 SHA-256: f8c21bfddee376c6574fab7c78eb32817fc82cffcf67c75e0716f3ff3f9393d2
156 Risk Score

Malware Insights

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

The PDF document contains numerous embedded URLs, many of which point to compromised WordPress sites acting as link farms. The ML classifier and ClamAV detection strongly indicate malicious intent, specifically identified as a phishing or trojan delivery mechanism. The document body is heavily obfuscated and appears to be non-readable content, suggesting its primary purpose is to host these malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

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://adbetelparaguay.com/wp-content/plugins/super-forms/uploads/php/files/40bb81a3ce91a648a4a11f1513f1191f/zavijidezuroxovuj.pdf In PDF document text
    • https://tuabogadoangel.com/wp-content/plugins/super-forms/uploads/php/files/6b3ce5259e686ae6ab6a0dee2bea1144/gitigawe.pdfIn PDF document text
    • https://iamluno.com/wp-content/plugins/formcraft/file-upload/server/content/files/16074d707a63d0---70973724602.pdfIn PDF document text
    • https://aduanaldelvalle.com/userfiles/file/jilefigego.pdfIn PDF document text
    • https://eyestech.in/wp-content/plugins/super-forms/uploads/php/files/6r4ho15fp5f235vdut5s5ubnhj/vibateludaba.pdfIn PDF document text
    • http://irmascaritasdejesus.org.br/wp-content/plugins/formcraft/file-upload/server/content/files/160b5ecfd6ffff---84110198485.pdfIn PDF document text
    • https://aliencosmicexpo.com/wp-content/plugins/formcraft/file-upload/server/content/files/160825393ea277---bubuzebanoxutogukefuse.pdfIn PDF document text
    • https://www.certificagreen.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606cfc699a039---kulekejibofisu.pdfIn PDF document text
    • https://bettenbaehren.de/wp-content/plugins/formcraft/file-upload/server/content/files/16071c492edb66---videxej.pdfIn PDF document text
    • https://www.elementstraining.co.uk/wp-content/plugins/super-forms/uploads/php/files/mpkrs8o8ts1recaq3fij8qgd06/devifemojivo.pdfIn PDF document text
    • http://profisystem.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160cfe0d5f40b7---32271293726.pdfIn PDF document text
    • https://advancedbusiness.co/wp-content/plugins/super-forms/uploads/php/files/41060892e2ff21b0017fa4b45e9bf86e/fitejew.pdfIn PDF document text
    • http://www.olympussverige.se/wp-content/plugins/super-forms/uploads/php/files/3p06c27urbjcbfckeu50ff0g22/mevusekexobo.pdfIn PDF document text
    • http://axiomestates.com/userfiles/file/xatorur.pdfIn PDF document text
    • http://wallsfamilyreunion.com/clients/876683/File/vurawajiwesiwuzowa.pdfIn PDF document text
    • http://al-bandak.com/userfiles/file/vezesejaroredi.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/1KS0DP0cxss/uplcv?utm_term=pied+beauty+critical+appreciationPDF 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e873.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE873 5132 bytes
SHA-256: b1a789d459fe9f5c1fc16830e71e71a7d932d773032deedce0829bf81e67332f
font_01_sfnt_off0000f9fc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF9FC 10748 bytes
SHA-256: 05e742dc0420118f8c59264449c04b6b881f7fcd774228b25e35e5a0d7515e5e