Malicious PDF — malware analysis report

Static analysis result for SHA-256 51ab8df8973e5df4…

MALICIOUS

PDF

71.5 KB Created: 2021-10-03 12:41:49 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: c90784350477eadbfaba9527f90ec3bf SHA-1: cecad809ee2a3a9be0ab3e1ba38cf6b01d1a825e SHA-256: 51ab8df8973e5df4b3f82d7a2859183fa5a8f9dbe11ccbd32928b43bce2f1936
156 Risk Score

Malware Insights

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

The PDF contains a link farm with numerous URLs, many pointing to disposable or compromised hosting. The ClamAV detection and ML classifier strongly indicate malicious intent, likely phishing or malware distribution via these links. The heuristic PDF_SEO_DISPOSABLE_LINK_FARM specifically highlights the use of disposable hosting for link farms, suggesting an attempt to obscure the true malicious destination.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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://buyyoutubelikes.com/ci/userfiles/files/41851462583.pdf In PDF document text
    • http://omonetach.pl/foto/ilustracje/file/vugosizezuzofitedowujugox.pdfIn PDF document text
    • https://sy-chemical.com/UserFiles/file/nulidigatusix.pdfIn PDF document text
    • http://chaitraglaze.com/uploads/83749890665.pdfIn PDF document text
    • http://talcmanagement.com/uploaded_files/userfiles/files/14087015193.pdfIn PDF document text
    • https://paramourpourbebe.bettygagne.ca/userfiles/file/lavitilenutelido.pdfIn PDF document text
    • http://aj-freight.com/ckfinder/userfiles/files/34073589021.pdfIn PDF document text
    • http://abnig.friendship-match.com/upload/files/45621910505.pdfIn PDF document text
    • http://videotour24.com/data/fckupload/file/sotus.pdfIn PDF document text
    • http://trips-in.com/ckupload/files/difinuju.pdfIn PDF document text
    • https://cananalimdar.com/wp-content/plugins/super-forms/uploads/php/files/imvq5qr7nchhciedaakurkn79e/zugagur.pdfIn PDF document text
    • https://pierrelemagicien.com/userfiles/file/57363879537.pdfIn PDF document text
    • https://hiddencliff.kr/FileData/ckfinder/files/20210921_3A21E46D9E2AF743.pdfIn PDF document text
    • https://senegal4d.com/contents/files/visefun.pdfIn PDF document text
    • http://kxqcgs.com/filespath/files/20210923200554.pdfIn PDF document text
    • http://cainghienbinhduong.com/uploads/userfiles/file/pikijimuloxijazeno.pdfIn PDF document text
    • https://dazzlin.co.uk/wp-content/plugins/super-forms/uploads/php/files/6dc8caf7764209dc2fa952cf5d818ce9/vepakotijerev.pdfIn PDF document text
    • http://neodev.space/wp-content/plugins/formcraft/file-upload/server/content/files/161591c99bd545---mufapimugasojagis.pdfIn PDF document text
    • https://notofthisgalaxy.com/wp-content/plugins/super-forms/uploads/php/files/0ebl2i7r0a9dq07ji2q2todesb/15569500407.pdfIn PDF document text
    • https://notarbrazda.cz/userfiles/file/In PDF document text
    • https://krantiservice.com/ckfinder/userfiles/files/37401276902.pdfIn PDF document text
    • http://rcot.by/pics/files/mewamapufekisusi.pdfIn PDF document text
    • http://www.village-gaulois.org/gestion/ckfinder/userfiles/files/20964266216.pdfIn PDF document text
    • https://hoffmanowska.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1613f1b5b0694c---doniterok.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=linux+scan+ip+for+open+portsPDF 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_off0000b17c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB17C 18052 bytes
SHA-256: 0d4051c071a854bf863c13368bee968966c041ad46120d1776a2e8512a9e6be3
font_01_sfnt_off0000dfdd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDFDD 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f7f4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF7F4 10588 bytes
SHA-256: a0d23435c3f535933d594f1fcdf91bfa924877709b741e007912850353c5ad24