Malicious PDF — malware analysis report

Static analysis result for SHA-256 4c7c16891f769840…

MALICIOUS

PDF

84.2 KB Created: 2021-09-21 07:48:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 2d36f8ad99aff1fbeb2184bb7b8652bd SHA-1: 8df696c12e25b4aa61c1102920d16ed24b7a1a8b SHA-256: 4c7c16891f76984040d1fad5544d37167213ee4002d2e61a7cca4b6ed401ce11
66 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file flagged by ML classifiers as malicious. It contains numerous external URIs, many pointing to disposable hosting, suggesting a link farm or SEO spamming operation. The presence of embedded URLs and the heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicate a coordinated effort to redirect users to a large number of distinct PDF files, likely to distribute malware or engage in phishing. No scripts were extracted, but the overall structure points to a malicious document delivery mechanism.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

Heuristics 4

  • 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://infrive.ru/uplcv?utm_term=pokemon+card+game+offline PDF link annotation
    • http://hdg-gmuend.de/userfiles/files/zimubotorubotikosagiru.pdfIn PDF document text
    • http://good163.cn/Uploadfiles/files/vinosusoporovagikin.pdfIn PDF document text
    • https://peterdegendt.be/file/21721399429.pdfIn PDF document text
    • http://vesimport.ru/userfiles/file/45287336196.pdfIn PDF document text
    • http://newmob.it/userfiles/files/43174594552.pdfIn PDF document text
    • http://123flower.doweb.kr/upload/files/78687416488.pdfIn PDF document text
    • http://uspeh-kursk.ru/ckfinder/userfiles/files/88957438690.pdfIn PDF document text
    • http://rc-modeller.se/images/file///vuwosepegidipesevugusa.pdfIn PDF document text
    • http://xlpe.net/Images_upload/files/xofudederijijowu.pdfIn PDF document text
    • http://kientrucsangtrong.com/plus/files/75961956070.pdfIn PDF document text
    • http://manegedebuitenwijck.nl/uploads/file/67397065096.pdfIn PDF document text
    • http://hani-bee.com/userfiles/files/kedonusodamulugigu.pdfIn PDF document text
    • http://mebel-moscow.com/content/xuploadimages/file/woxajasixinetogutuji.pdfIn PDF document text
    • https://www.chauffeur-prive-nice.fr/wp-content/plugins/formcraft/file-upload/server/content/files/16138f353c7343---38067296515.pdfIn PDF document text
    • http://apismorava.eu/docs/mamasofu.pdfIn PDF document text
    • http://villabrown.it/userfiles/files/21651053048.pdfIn PDF document text
    • https://elemental-ia.com/userfiles/file/veler.pdfIn PDF document text
    • https://lederstuehle-shop.de/ckfinder/userfiles/files/jetegeg.pdfIn PDF document text
    • https://ichibaninfotech.com/ckfinder/userfiles/files/bawozazufajuwaj.pdfIn PDF document text
    • http://siamsankyo.com/Uploads/file/79898483487.pdfIn PDF document text
    • https://fratellifurloni.it/file/89954337388.pdfIn PDF document text
    • https://vegas-shop.net/uploads/files/59774084829.pdfIn PDF document text
    • http://gdfsztal.com/uploadfile/files/sagobakuriliwomarisal.pdfIn PDF document text
    • http://www.elmundodelapiscina.com/ckfinder/userfiles/files/gokegudenunudufutujexamol.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_off0000e4dc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE4DC 10648 bytes
SHA-256: 50ac0017acf6e3bb9bf46c351c0a824953f2555347768b87cf5f53a7fcfe04c4
font_01_sfnt_off0000fcf6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFCF6 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011508.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11508 17808 bytes
SHA-256: 44033625e0ec5d1ab91907e29a9f4d6644e4e0a9d9d4ac04bb43b8becb90d3f0

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