Malicious PDF — malware analysis report

Static analysis result for SHA-256 733399faef4267a5…

MALICIOUS

PDF

81.1 KB Created: 2021-09-16 04:08:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 6dcb4b11fcc1da63ff21f0b1cb9e1200 SHA-1: b5f3443d70f905fe93966018a414438b5f2c7f6a SHA-256: 733399faef4267a58ad31233ab094da7464836d71fbc11ae92e09494db06eb1e
156 Risk Score

Malware Insights

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

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with numerous external URIs pointing to potentially compromised or disposable hosting. The document body is heavily obfuscated, suggesting an attempt to hide its true malicious nature.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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 https://wastran.ru/uplcv?utm_term=how+do+i+switch+from+iphone+to+android PDF link annotation
    • https://wonwon.taipei/photo/file/60522973000.pdfIn PDF document text
    • http://xhiehchin.com/Xhieh_News/_file/neraxinuseluxodigalopon.pdfIn PDF document text
    • http://thebrownbag.vn/upload/files/51467882366.pdfIn PDF document text
    • http://ototavandosemesi.com/resimler/file/fugaledenimituxoke.pdfIn PDF document text
    • https://www.frontiermyanmar.com/sites/all/libraries/ckfinder/userfiles/files/76857988389.pdfIn PDF document text
    • https://webmodels.studio/wp-content/plugins/formcraft/file-upload/server/content/files/1613801604b491---lenavopuwaduxixunolil.pdfIn PDF document text
    • http://www.dereformasenalicante.com/archivos/files/2869462452.pdfIn PDF document text
    • http://www.temaricerca.com/entry2013/admin/ckfinder/userfiles/files/6010911516.pdfIn PDF document text
    • http://masonhn.com/d/files/xilekovafabananozijopa.pdfIn PDF document text
    • http://33podarka.ru/pictures/files/xilewatape.pdfIn PDF document text
    • http://www.hj-bouwt.be/wp-content/plugins/formcraft/file-upload/server/content/files/1612fb735c1a8a---bekep.pdfIn PDF document text
    • http://vrajacreation.com/uploaded_files/userfiles/files/gezorozame.pdfIn PDF document text
    • http://www.korayozelguvenlik.com/wp-content/plugins/formcraft/file-upload/server/content/files/16130674656c4b---47809612661.pdfIn PDF document text
    • https://kipass.fr/userfiles/file/6466065375.pdfIn PDF document text
    • http://sinojjacob.com/userfiles/file/20271309624.pdfIn PDF document text
    • http://www.leesii.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613f4b70bc7bd---21670268641.pdfIn PDF document text
    • https://www.bouwenaaneensterkwerkgeversmerk.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1613a22645e8fb---vewebixurikolopite.pdfIn PDF document text
    • http://jonme.net/ckupload/files/18909769653.pdfIn PDF document text
    • https://nicklason.se/ckfinder/userfiles/files/kepoxuwumi.pdfIn PDF document text
    • http://naszymsladem.pl/upload/file/jelesesesibizawobu.pdfIn PDF document text
    • http://torby.kbo.pl/ckfinder/userfiles/files/87051424158.pdfIn PDF document text
    • https://dichvumayphoto.vn/webroot/img/files/40772526959.pdfIn PDF document text
    • http://aroma-es.site/yamituki-n/uploads/files/55234257442.pdfIn PDF document text
    • https://qboardapp.com/wp-content/plugins/super-forms/uploads/php/files/29e54af21e0d120b7507a0fcaca7d6ad/juzuzonesavo.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_off0000d97a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD97A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f191.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF191 10916 bytes
SHA-256: da4c6b041d50e53f47b9df166752f5481832e6498400d374fbdc72c2412902b7
font_02_sfnt_off00010aac.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10AAC 17192 bytes
SHA-256: 7ee6033fc5639a863aac12ee5b0fa3d9c37a70e77f0fbac7a03a958e536c460e