Malicious PDF — malware analysis report

Static analysis result for SHA-256 51d96efa416e6169…

MALICIOUS

PDF

67.5 KB Created: 2021-06-07 18:42:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-27
MD5: f78af072fbb5e6709f97f0c5acf0a103 SHA-1: ff5263a7906f33386304ef85ff640f6b7531c0b9 SHA-256: 51d96efa416e6169ce0287c4d94917fae21266e2f723c7d6e7884fa1ba9fc8b1
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF file contains numerous embedded URLs, many of which point to compromised WordPress sites and are structured as link farms. The ML classifier and ClamAV detection strongly indicate malicious intent, specifically phishing or malware distribution. While no scripts were directly extracted, the PDF structure and URL patterns are consistent with techniques used to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://krisoc.ru/uplcv?utm_term=how+to+measure+communication+skills+in+an+interview PDF link annotation
    • https://boldvision.tv/wp-content/plugins/formcraft/file-upload/server/content/files/1606db9efc6bd2---16330792930.pdfIn PDF document text
    • http://www.morenoroofing.com/wp-content/plugins/formcraft/file-upload/server/content/files/16087489058bc7---lesiwemijimap.pdfIn PDF document text
    • http://cricalliance.com/wp-content/plugins/formcraft/file-upload/server/content/files/160715d1ea526e---28693763663.pdfIn PDF document text
    • http://www.bufolari.com/public/immagini/file/92112563757.pdfIn PDF document text
    • https://a1-recruitment.fr/v2011/Files/fck_upload/file/tibunoba.pdfIn PDF document text
    • https://abril.pe/wp-content/plugins/super-forms/uploads/php/files/1q6hbtfvvocem5kn05vo4hv2q5/56339368911.pdfIn PDF document text
    • http://call.ae/wp-content/plugins/formcraft/file-upload/server/content/files/160833cb7e46bb---8729987327.pdfIn PDF document text
    • http://www.kinoimaging.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1609f0e074cc34---nemuxarukuzikibazud.pdfIn PDF document text
    • https://dazzlin.co.uk/wp-content/plugins/super-forms/uploads/php/files/dd0e6b2f427ab2d46cfb3d5f2a8f3e28/92376220588.pdfIn PDF document text
    • http://www.vivelamusica.es/wp-content/plugins/formcraft/file-upload/server/content/files/16095842b33ced---wulowapisexaxexeribusiw.pdfIn PDF document text
    • http://www.sunarpazarlama.com/wp-content/plugins/super-forms/uploads/php/files/3518ak944ngnac4kih5teknok2/patoziwawixikosorupol.pdfIn PDF document text
    • http://kulturazebrak.cz/userfiles/texixoxolep.pdfIn PDF document text
    • http://www.nationaalgolfcongres.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16098c0e33c482---lasadeviwa.pdfIn PDF document text
    • http://churchliferesources.org/wp-content/plugins/formcraft/file-upload/server/content/files/160a9ce3fbe4af---xogijurosinexidaf.pdfIn PDF document text
    • https://michelbarbot.com/upload/files/lipifategidamuvofenalamax.pdfIn PDF document text
    • http://www.skup.it/wp-content/plugins/formcraft/file-upload/server/content/files/16096d7aad3e51---xodopanivelu.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000cd2e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCD2E 5120 bytes
SHA-256: af973538214753abed588cd6ccdfd646cb04da47428b4eb227941ebfb7fee71f
font_01_sfnt_off0000de95.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE95 10004 bytes
SHA-256: 7280ef5da0049e91e93008437bc3835166ac7ece516a1b356ce8bf20962a42d1