Malicious PDF — malware analysis report

Static analysis result for SHA-256 81b4e0d78c22c176…

MALICIOUS

PDF

81.4 KB Created: 2021-09-16 13:50:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 79c6d4e4c8896cbef970df76d0e96126 SHA-1: 1759c4282270ebb2e67f5a174612de21f0b85cde SHA-256: 81b4e0d78c22c176786d4179158e483c4f3c022b912f39a81198c4a02e74f890
156 Risk Score

Malware Insights

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

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics reveal it functions as a link farm, directing users to external sites, some hosted on compromised CMS uploads and disposable domains. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic specifically points to a tactic of using link farms on disposable hosting to potentially distribute malware or phish for credentials.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

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://isemya.by/modules/ariol/static/ariol/ckfinder/files/xojugeli.pdf In PDF document text
    • https://sofupingame.net/calisma2/files/uploads/6370188362.pdfIn PDF document text
    • http://xn--h1aeekk.xn--p1ai/files/file/75116670731.pdfIn PDF document text
    • https://autosofortkauf.ch/wp-content/plugins/super-forms/uploads/php/files/d2h73ruupvi6pk4qj57rl33iiu/8434321535.pdfIn PDF document text
    • http://pomocnaukowa.net/Upload/file/sulume.pdfIn PDF document text
    • https://superpackeg.com/userfiles/file/75877068524.pdfIn PDF document text
    • http://webcertain.ca/contentupload/fckeditorUploads/organization_/file/letumujedulirexaxeluz.pdfIn PDF document text
    • http://phuocthuan.vn/images/pic/file/sojixetibivelofedabega.pdfIn PDF document text
    • http://thevisionkharj.com/userfiles/files/befolokepivasadodaxu.pdfIn PDF document text
    • http://dorrstrechy.cz/UserFiles/File/fededase.pdfIn PDF document text
    • http://localhomesales.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16132d27c41347---36439475220.pdfIn PDF document text
    • http://agisma.ru/files/pages/files/mukuwurugumav.pdfIn PDF document text
    • http://luluscafeonline.com/uploads/files/83289423855.pdfIn PDF document text
    • https://artsketch.ru/wp-content/plugins/super-forms/uploads/php/files/dff6ecab13960588768c67afc79b07c0/pufoxogugujubidonurifurub.pdfIn PDF document text
    • http://tutaylamhet.com/storage/ckfinder/files/66662746363.pdfIn PDF document text
    • http://antik-cafe-bergen.de/wp-content/plugins/formcraft/file-upload/server/content/files/16142026d001bf---97518002096.pdfIn PDF document text
    • http://baharev76.ru/userfiles/file/gegetilofifedenuvox.pdfIn PDF document text
    • https://duongthuy.net/userfiles/file/gifezub.pdfIn PDF document text
    • http://elektro-galerie-hamburg.de/userfiles/file/89780658127.pdfIn PDF document text
    • http://zsdbiopharm.com/upload/files/5892429172.pdfIn PDF document text
    • https://www.lipfish.no/wp-content/plugins/formcraft/file-upload/server/content/files/1614093179a385---zodugekawadutakug.pdfIn PDF document text
    • http://zhengfutz.com/v15/Upload/file/2021981637227964.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/PmAiG5ZyT-k/uplcv?utm_term=matematicas+3+pdfPDF 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_off0000d9f2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD9F2 17668 bytes
SHA-256: d178ed45b5e8ab3d63a6b4de507374f8dfb1eb4015d79923c3e872ecb7736f4d
font_01_sfnt_off000107e0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x107E0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011ff7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11FF7 10576 bytes
SHA-256: 616b61c3d2d05a85e531281cfb0e6390fb385678574383e2be06ec542e5f8369