Malicious PDF — malware analysis report

Static analysis result for SHA-256 b87d34efad8f53cf…

MALICIOUS

PDF

82.9 KB Created: 2021-09-15 21:34:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 67a814a0a3866ac8bf1dfd91f5c7eab2 SHA-1: 16c6b5d70eac44087a9686e5cf0638108d412ca0 SHA-256: b87d34efad8f53cfc28ce8bc967e8ae8e0870b72145d4f4a7ab50509139d179d
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous external links, with several heuristics flagging it as a link farm on disposable hosting and containing algorithmically-generated URLs. The ClamAV detection and ML classifier strongly indicate malicious intent, likely for phishing or distributing further malware. Although no scripts were explicitly extracted, the PDF structure and URL patterns are consistent with malicious documents.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9917

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 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.
  • 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=4+letter+words+starting+with+ha PDF link annotation
    • https://sieuthimaycafe.vn/uploads/file/78249833653.pdfIn PDF document text
    • https://jancsoalapitvany.hu/ckfinder/userfiles/files/65170735194.pdfIn PDF document text
    • http://www.mousumibanerjee.com/fckimages/file/mekafumowironege.pdfIn PDF document text
    • http://chanakol.com/ckfinder/userfiles/files/vurujim.pdfIn PDF document text
    • https://maftplayer.net/calisma2/files/uploads/kamagedax.pdfIn PDF document text
    • http://gdlianyu.com/uploadfiles/file/wamoserukusigotivupafox.pdfIn PDF document text
    • http://acrclubinversores.com/files/galeria/files/11358044655.pdfIn PDF document text
    • https://www.hdontheroadnapoli.it/wp-content/plugins/formcraft/file-upload/server/content/files/1612f2649d4332---nuvote.pdfIn PDF document text
    • https://robert-zauer.cz/userfiles/file/gomitujenavadosami.pdfIn PDF document text
    • http://sipzip.com/userfiles/file/1941005116.pdfIn PDF document text
    • http://wwpokebar.com/uploads/files/sazibokirovu.pdfIn PDF document text
    • https://horacebatten.com/ckfinder/userfiles/files/tovufitapolixef.pdfIn PDF document text
    • https://inclinedigital.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613e67b447cb9---bukopegop.pdfIn PDF document text
    • http://tznjl.com/userfiles/files/kisokepowepewukusaguzuzu.pdfIn PDF document text
    • http://giteduguedesboires.fr/userfiles/file/81616257961.pdfIn PDF document text
    • https://xuantruongtech.com/images/ckeditor/files/sitigisamekizisavumadoxa.pdfIn PDF document text
    • http://www.tecs4.com/intranet/ckfinder/userfiles/files/21119774361.pdfIn PDF document text
    • http://energcomb.net/cms_enercomb/sgi_userfiles/userfiles/files/6354652935.pdfIn PDF document text
    • https://cuichi177.com/uploads/files/202109070402342851.pdfIn PDF document text
    • http://binhchuachay.info/Images_upload/files/17689180574.pdfIn PDF document text
    • http://perilatomsk.ru/ckfinder/userfiles/files/tixokefanuxapet.pdfIn PDF document text
    • http://ambulatorioveterinariopisillibertozzi.eu/userfiles/files/63236992917.pdfIn PDF document text
    • http://www.wiz-fac.com/uploadImg/file/gufutulefepifesita.pdfIn PDF document text
    • https://cortemadera.com/wysiwygfiles/file/23613670230.pdfIn PDF document text
    • https://emilline.dk/ckfinder/userfiles/files/fagewuketorikedakikakanab.pdfIn PDF document text
    • http://actinq.nl/upload/file/55267850344.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_off0000df64.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF64 10596 bytes
SHA-256: 076f1eec3b6e0211757302babab7cee7d377fdaa677a262cdd85858b97ea858a
font_01_sfnt_off0000f759.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF759 17896 bytes
SHA-256: ffc0afc8ce083bfeafcc1899560715bdc996236565580a40077c4c54bd7aa956
font_02_sfnt_off00012594.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12594 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1