Malicious PDF — malware analysis report

Static analysis result for SHA-256 cb55a65d6febdbc7…

MALICIOUS

PDF

80.6 KB Created: 2021-09-05 22:46:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: 5d55f7706d90f07eaefb2fb332e2e44a SHA-1: 82f4d625583a5bfa7afe1c48258483a8b3b6a153 SHA-256: cb55a65d6febdbc7f3ed2b0871937cfd19c2475ded2e84cba2294d968d79abac
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file flagged by ML classifiers and ClamAV as malicious. It contains numerous embedded URLs, many pointing to compromised websites or disposable hosting, suggesting a link farm or phishing lure. The presence of PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics indicates attempts to leverage SEO or compromised infrastructure for distribution. No scripts were extracted, but the overall structure points to a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://lnshiyue.com/userfiles/file/20210531043008_2032272572.pdf In PDF document text
    • http://interiorconsignments.com/media/file/54900035426.pdfIn PDF document text
    • http://bluekeydigital.com/images/pic/file/41132414214.pdfIn PDF document text
    • https://realwebguys.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608033acd769f---85970988927.pdfIn PDF document text
    • https://www.pal-kont.hu/wp-content/plugins/super-forms/uploads/php/files/4c20806c7e6c377cc27511ee840a2645/86542009213.pdfIn PDF document text
    • http://rencontres-icare.org/userfiles/file/1539593753.pdfIn PDF document text
    • https://comfortinnbarrie.com/phpsites/vertical_living/uploads/file/redakiwitufowoxi.pdfIn PDF document text
    • https://madame-tina.com/ckfinder/userfiles/files/kofolukotixud.pdfIn PDF document text
    • http://talcmanagement.com/uploaded_files/userfiles/files/54918266559.pdfIn PDF document text
    • https://skvely-kup.cz/files/file/povigagalaja.pdfIn PDF document text
    • http://www.nbrownies.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/161157ba6bfd46---37274942764.pdfIn PDF document text
    • http://aksaaydinlatma.com/img/editor/image/file/75444315400.pdfIn PDF document text
    • https://chongtham68.com/app/webroot/uploads/files/96421413226.pdfIn PDF document text
    • http://www.alex-vasilkov.ru/images/wisdom/file/87412009901.pdfIn PDF document text
    • http://firanywiktoria.pl/uploads/editor/file/xafavawumeroso.pdfIn PDF document text
    • https://robotics-institute.com/wp-content/plugins/super-forms/uploads/php/files/o62h6i31iqkcr64j0s4u2h79p4/22812613513.pdfIn PDF document text
    • http://deurenhanger.nl/userfiles/file/medusesidixaferi.pdfIn PDF document text
    • https://bhandarisurgical.com/ckfinder/userfiles/files/segovobeku.pdfIn PDF document text
    • https://www.advids.io/wp-content/plugins/formcraft/file-upload/server/content/files/1611189ce4e1e8---14301136595.pdfIn PDF document text
    • http://www.gametimecatering.com/wp-content/plugins/formcraft/file-upload/server/content/files/160854e07060e5---pedumitusavufovarobi.pdfIn PDF document text
    • http://szolnokepul.hu/userfiles/file/47597723306.pdfIn PDF document text
    • http://mdsalon.ru/img/lib/file/meloxi.pdfIn PDF document text
    • http://saeronbio.com/userData/board/file/lelazugiriradu.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/S30rS-6n6vg/uplcv?utm_term=scientific+method+worksheet+3rd+gradePDF 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_off0000d7cd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD7CD 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000efe4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEFE4 11304 bytes
SHA-256: ee7e665c8800ca78eaff01344ef74e8e36cfb5ab00ca19639631cdf3e33dc944
font_02_sfnt_off00010a22.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A22 16424 bytes
SHA-256: aa1a6153019720c65c34907b7a284c9a77ac38ca757f612ec2dbdb1f31c1aa48

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