Malicious PDF — malware analysis report

Static analysis result for SHA-256 8c285995dd40ebe7…

MALICIOUS

PDF

79.8 KB Created: 2021-09-14 09:10:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: f34658974d78f29f9e22f3b8e05b52cf SHA-1: 50610b32e024b37feaf2b15d0ba41299841af42c SHA-256: 8c285995dd40ebe7cc5b25714f1bc3e2d9dfb49b47c2291f823ccfd5de764146
156 Risk Score

Malware Insights

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

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to multiple external URLs hosted on potentially compromised or disposable domains. The presence of numerous PDF_URI and PDF_SEO_DISPOSABLE_LINK_FARM firings strongly suggests a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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 https://allytemp.ru/uplcv?utm_term=audio+mp3+cutter+mix+converter+and+ringtone+maker+pro+apk PDF link annotation
    • https://www.lesson-online.org/wp-content/plugins/super-forms/uploads/php/files/o0bousu7kijr2ii71d37eogsl6/64089529439.pdfIn PDF document text
    • http://amicissiapiemonteisa.it/userfiles/files/ruzunuwelopu.pdfIn PDF document text
    • http://geologocarmignani.com/userfiles/files/76184070763.pdfIn PDF document text
    • http://joyandwowbook.com/upload/file/zuraxowodip.pdfIn PDF document text
    • http://sabaispa.net/userfiles/file/94045976743.pdfIn PDF document text
    • http://studioarchterreni.it/userfiles/files/pekaxuwururezabo.pdfIn PDF document text
    • http://phantasos.org/userfiles/file/11616639957.pdfIn PDF document text
    • http://www.dr.schure.net/ckfinder/userfiles/files/rukogap.pdfIn PDF document text
    • https://cihangirhotel.com/upload/ckfinder/files/pulebaxidizusipofil.pdfIn PDF document text
    • http://niezapominajkowo.eu/userfiles/file/1556264486.pdfIn PDF document text
    • http://hoangle.vn/uploads/userfiles/file/68480310564.pdfIn PDF document text
    • http://cee1968.com/ckfinder/userfiles/files/ziwasefifufufifudixekuw.pdfIn PDF document text
    • https://www.andeanskyline.com/wp-content/plugins/formcraft/file-upload/server/content/files/161402b779e700---fezumexotaparemiwalu.pdfIn PDF document text
    • http://auto4-spb.ru/public/images/ckfinder/files/malotubitotagebutanatam.pdfIn PDF document text
    • http://uhy-th.com/image/upload/files/tanovagalewomunanuf.pdfIn PDF document text
    • https://sibiucuratenie.ro/fckeditor/userfiles/file/rewozopolezawigivi.pdfIn PDF document text
    • http://sujitonweb.com/userfiles/files/ruwejanudogiwero.pdfIn PDF document text
    • http://recruiters-zone.com/wp-content/plugins/formcraft/file-upload/server/content/files/16130db1b214cf---59394646394.pdfIn PDF document text
    • http://www.naturhalles.fr/fckeditor/userfiles/file/pixewuwi.pdfIn PDF document text
    • http://ccsl.asia/files/boribiwadud.pdfIn PDF document text
    • http://kadh.kr/bobod/upload/file/ruzusotukubomejuso.pdfIn PDF document text
    • https://machinex-machines.com/UserFiles/File/datewokimijuvusidekiwo.pdfIn PDF document text
    • http://www.emporiocaritaspisa.it/wordpress/wp-content/plugins/formcraft/file-upload/server/content/files/16135601457681---93044364750.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_off0000d226.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD226 17192 bytes
SHA-256: 1a435cc98bc9e455e4e417b55645e91824e0669ae09ff293d9748aa55d8e466c
font_01_sfnt_off0000fea4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFEA4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000116bb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x116BB 11156 bytes
SHA-256: ee9375465955d998f5a144743975b4f03a57090479b1c28e3fd9a2b66075cc1e