Malicious PDF — malware analysis report

Static analysis result for SHA-256 8136df351abe2637…

MALICIOUS

PDF

71.9 KB Created: 2021-09-26 03:32:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: a429f21952a911f3738da4eff83ed3b1 SHA-1: 8b7fa67d1f5d98d0e42ce42201f17d2a16817522 SHA-256: 8136df351abe2637d51275f144f68704175b2da3d3548ccb428ec71db7967ca1
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file that contains numerous links to external websites, many of which are hosted on compromised WordPress sites or disposable domains. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The presence of embedded URLs and the nature of the heuristics suggest the document is designed to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 7

  • 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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://jyjjapan.jp/files/ckeditor/files/98628122475.pdf In PDF document text
    • http://cameronhaddock.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f1ee441c8f---73222096421.pdfIn PDF document text
    • https://west-holding.com/userfiles/file/tojadatepulemi.pdfIn PDF document text
    • http://otoozevran.com/resimler/files/giteg.pdfIn PDF document text
    • http://ophtalmic-overnight.fr/wp-content/plugins/formcraft/file-upload/server/content/files/161319e66349a5---62118398064.pdfIn PDF document text
    • https://renault-service.com/userfiles/34610508413.pdfIn PDF document text
    • http://biafrapol.pl/pliki/file/setomaxutazetete.pdfIn PDF document text
    • http://www.allatpatikapecs.hu/images/file/judofaw.pdfIn PDF document text
    • http://fedime.org/imagenes/digonaperatupuka.pdfIn PDF document text
    • https://directprocessors.com/wp-content/plugins/formcraft/file-upload/server/content/files/16135032e3efb9---33038470087.pdfIn PDF document text
    • http://sun-green.de/ckfinder/userfiles/files/97749155275.pdfIn PDF document text
    • http://www.bestlifepolicy.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1613cb14b5a8ee---79759249374.pdfIn PDF document text
    • http://birkhoffhi.com/userfiles/files/kirijadebipuvisax.pdfIn PDF document text
    • http://smsgurugram.com/miet/assets/files/tojodowogowanu.pdfIn PDF document text
    • http://www.psoealora.es/ckfinder/userfiles/files/27824086294.pdfIn PDF document text
    • http://www.sunarnuricomuisvealisverismerkezi.com/wp-content/plugins/super-forms/uploads/php/files/m1rpng9safeh4b6gsqp9t3l9o2/mibowu.pdfIn PDF document text
    • http://dogable.de/userfiles/file/63327894682.pdfIn PDF document text
    • https://web-sila.ru/wp-content/plugins/super-forms/uploads/php/files/3cc1da4b8bb2348f8ee7287c017cb9f6/82164946000.pdfIn PDF document text
    • https://dmshospital.com/mm_engg/files/vulenizumogegis.pdfIn PDF document text
    • http://termosystem.pl/userfiles/file/xetitexirasawulolurigale.pdfIn PDF document text
    • http://france-ex.com/images/blog/file/kixijimokisub.pdfIn PDF document text
    • http://ridendo.cz/files/file/daxuzutu.pdfIn PDF document text
    • https://reclamesticker.nl/images/uploads/file/In PDF document text
    • https://egokituz.org/files/galeria/files/gikoligukomipolelizopopu.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/DOqCt-cVA4I/uplcv?utm_term=accessibility+suite+appPDF 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_off0000b5cb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB5CB 17404 bytes
SHA-256: 24319834b7f789fb8348a83775ebb0c85f5bd4e2859d4d4cdda1d66c917f34ae
font_01_sfnt_off0000e23e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE23E 10380 bytes
SHA-256: 56b5f399a47f3935387d92cf95dcb4e3b498e37c8da0e42feeed5195788c5d8c
font_02_sfnt_off0000f9b9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF9B9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1