Malicious PDF — malware analysis report

Static analysis result for SHA-256 551efd81ce272bc2…

MALICIOUS

PDF

78.7 KB Created: 2021-09-19 02:21:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: d5b4fd21e29ecf6be852bace1e4e0e90 SHA-1: 1a7163a6b0398217e5c8be70d111be22bfd6286b SHA-256: 551efd81ce272bc2e4f3299c4a8c515689e32a12f283f0080155aa71d2cb3ab8
156 Risk Score

Malware Insights

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

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The heuristics reveal it functions as a link farm, with numerous URLs pointing to compromised WordPress sites and other disposable hosting. These links likely serve as redirects to phishing pages or malware download sites, a common tactic for initial compromise.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9958

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://medvor.ru/uplcv?utm_term=adding+subtracting+multiplying+and+dividing+fractions+worksheet PDF link annotation
    • https://www.growxponential.com/wp-content/plugins/super-forms/uploads/php/files/s9npokaoqc9ff6gfq4fjv9g8v3/xigofabekasunekojititor.pdfIn PDF document text
    • https://nationalcardsolutions.com/wp-content/plugins/formcraft/file-upload/server/content/files/161364c02e96c5---ligine.pdfIn PDF document text
    • https://studybrilliant.online/app/webroot/img/userfiles/file/xixasusojamidulugeluvovob.pdfIn PDF document text
    • http://kpdb.org/userfiles/files/mezasiribesafemagaviki.pdfIn PDF document text
    • http://elsped.hu/files/file/15646174658.pdfIn PDF document text
    • http://structurecreative.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613b2a1db920e---61448078641.pdfIn PDF document text
    • http://nenorm.com/files/files/gorezixux.pdfIn PDF document text
    • https://www.18fire.com/wp-content/plugins/super-forms/uploads/php/files/35d56234378d7a04a930557fe6220fe5/tuzosipawalirupexexa.pdfIn PDF document text
    • https://rajakedua.com/contents/files/2076161571.pdfIn PDF document text
    • http://clinton.abwingsmd.com/uploads/files/42252931902.pdfIn PDF document text
    • http://cheapneasytrafficschool.com/CheapNEasyTrafficSchool/pa/trainstation/uploads/image/file/mekinudubat.pdfIn PDF document text
    • http://www.drop-lok.com/wp-content/plugins/formcraft/file-upload/server/content/files/161322163ced2c---doresexonutovomebi.pdfIn PDF document text
    • http://arredamenticucinesiciliane.it/userfiles/files/zubimuxow.pdfIn PDF document text
    • http://crystaltrade.hu/data/file/zexivixalesolevojabaxe.pdfIn PDF document text
    • http://hydrogears.com/survey/userfiles/files/zeludosanuxel.pdfIn PDF document text
    • https://www.gml.de/wp-content/plugins/formcraft/file-upload/server/content/files/1613c544d7b2a0---nakuj.pdfIn PDF document text
    • https://kenhquangcao.vn/uploads/files/danifizisavaxamulolu.pdfIn PDF document text
    • http://vpsystem.com/files/fck/nurukipudap.pdfIn PDF document text
    • http://topimmigrationlawyer.org/ckfinder/userfiles/files/32260130238.pdfIn PDF document text
    • http://e-motyle.natura2000.pl/imgturysta/files/93488814266.pdfIn PDF document text
    • https://greenlandpark.com/uploads/files/80050717051.pdfIn PDF document text
    • https://ahirealty.in/admin/userfiles/files/sotoganenekiwemalokig.pdfIn PDF document text
    • http://www.pacautomarketing.com/file/rijojo.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_off0000cc8d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCC8D 17376 bytes
SHA-256: 6af01d16e17b554f4269025ad2fa7f8a8dd4f8a7ec6c47a59c19ebf73fbfc27c
font_01_sfnt_off0000f973.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF973 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001118a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1118A 11644 bytes
SHA-256: 5895364d1764442bffe91c5c858ca6c8b182662ae338962512fc993573ad383e

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