Malicious PDF — malware analysis report

Static analysis result for SHA-256 921c90f1a4061082…

MALICIOUS

PDF

82.9 KB Created: 2021-09-24 02:06:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 90414f19ad02ca03fc52068d7a1ee0af SHA-1: 1782500b2a7b4a89cc441910bd9cc371546343dd SHA-256: 921c90f1a406108284fa5f8bff92a1268ff7cc63ad013f906af1ad46ea430f63
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was detected as malicious by ClamAV and an ML classifier. It contains numerous embedded URLs, many pointing to compromised WordPress sites or disposable hosting, suggesting a link farm designed to redirect users. The heuristic PDF_SEO_DISPOSABLE_LINK_FARM specifically indicates this pattern. While no scripts were explicitly extracted, the nature of the embedded URLs and the PDF format itself often implies the use of JavaScript for redirection or obfuscation, hence the T1059.007 technique.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

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://krisoc.ru/uplcv?utm_term=inshot+video+download PDF link annotation
    • http://www.opencalgary.org/wp-content/plugins/formcraft/file-upload/server/content/files/1613a0a693a0c8---61201667550.pdfIn PDF document text
    • http://cp-tournament.org/ckfinder/userfiles/files/romot.pdfIn PDF document text
    • http://drukarnia-warszawa.pl/pliki/file/wosifuwupexunuro.pdfIn PDF document text
    • http://traslochimontalto.it/userfiles/files/zuzizaxek.pdfIn PDF document text
    • http://sellmysayarah.com/userfiles/files/50158850499.pdfIn PDF document text
    • https://faktxeber.com/resimler/files/vonov.pdfIn PDF document text
    • http://www.orarestauratorisaf.it/wp-content/plugins/formcraft/file-upload/server/content/files/1613f99b283dbc---73562297152.pdfIn PDF document text
    • https://zegaoyun.com/calisma2/files/uploads/ritukozifufowosovefa.pdfIn PDF document text
    • https://elmawadah.com/userfiles/file/63164734536.pdfIn PDF document text
    • http://klaaswester.nl/img/file/mopetepav.pdfIn PDF document text
    • http://csp.hu/editor_up/56726110441.pdfIn PDF document text
    • http://uts.edu.co/portal/app/ckfinder/userfiles/files/1478540624.pdfIn PDF document text
    • http://abwplazaview.com/uploads/files/kisusif.pdfIn PDF document text
    • http://master-stroi76.ru/userfiles/file/92363043667.pdfIn PDF document text
    • https://escolaalfa.com/userfiles/file/riwoguwedaresevuwoveleg.pdfIn PDF document text
    • https://teplitsyoptom.ru/wp-content/plugins/super-forms/uploads/php/files/c93c2b9d9547c424dbbc3e0ce13f25df/kosekufawatiruw.pdfIn PDF document text
    • http://gvs-russia.ru/admin/ckfinder/userfiles/files/77873986613.pdfIn PDF document text
    • http://theponghop.com/upload/files/nafafigelopepenaneguned.pdfIn PDF document text
    • http://bftt.marketsearching.com/upload/files/71567914132.pdfIn PDF document text
    • http://sun-green.be/ckfinder/userfiles/files/29719488537.pdfIn PDF document text
    • http://first-group.kr/ckupload/files/wuvixokimozebunorofesi.pdfIn PDF document text
    • http://lynxauto.ru/userfiles/file/vopexubamajololakada.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_off0000e0b2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE0B2 17772 bytes
SHA-256: 9168251d11d882a52d474e870b4fbf9fe1176b3d3e7e1aff1228f607549e07b0
font_01_sfnt_off00010e9a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10E9A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000126b1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x126B1 10348 bytes
SHA-256: 5c8e73bfb8db53dc6146fcacd170f3fef3c67584c551bba15d9989f1528e4bc6