Malicious PDF — malware analysis report

Static analysis result for SHA-256 66e53595e677bf20…

MALICIOUS

PDF

70.2 KB Created: 2021-09-28 04:12:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 3aa83a90e03536504ec6385ee44004f0 SHA-1: 08634db32c4cdc7bc544e7795175a82c59ceaaa2 SHA-256: 66e53595e677bf2064ec3779b74881b670f0e7485c2e9d52c24c1d2ef5393bd6
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file was flagged by multiple heuristics as malicious, including a critical ClamAV detection and an ML classifier. It contains numerous embedded URLs, many of which point to compromised CMS upload storage or are part of a link farm on disposable hosting. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

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://votejoedestefano.com/editorData/file/6694344617.pdf
    • http://esebtekstil.com/resimler/files/mizaperikuxebak.pdf
    • http://shopcode.ru/uploads/file/9735863163.pdf
    • http://nieruchomosci-swidnica.pl/userfiles/file/30621527338.pdf
    • https://vhcvietnam.vn/ckeditor/images/files/10685366737.pdf
    • https://www.burit.net/wp-content/plugins/formcraft/file-upload/server/content/files/1612f10b9315e6---rugupinufupixapepobirepu.pdf
    • https://grnca.org/img/files/files/fumawulelamivufajom.pdf
    • http://emailreceptionist.net/userfiles/file/lezigutimokogosap.pdf
    • https://www.tahitotfaluovodak.hu/ckfinder/userfiles/files/95860043050.pdf
    • https://nbcmedia.vn/ckfinder/userfiles/files/61729318051.pdf
    • http://salamino.pl/userfiles/file/bufokojujizagaxonaxa.pdf
    • http://studiospazioambiente.it/userfiles/files/89377563877.pdf
    • http://etoprosto.ru/ckfinder/userfiles/files/gulugenexasodexezupivavok.pdf
    • http://brucemayrockinstitute.com/assets/ckfinder/core/connector/php/uploads/files/kimukarolezexe.pdf
    • https://easypayindia.in/userfiles/file/46668083119.pdf
    • https://tp-pos.com/uploads/image/files/bitexulexemaxobodesakuneb.pdf
    • https://istanajp2.com/contents/files/35632999205.pdf
    • https://wamsconference.com/wp-content/plugins/super-forms/uploads/php/files/c9b1bc0603b47ebfb48984142cdaa4e2/44867863515.pdf
    • http://pokorny-podlahy.cz/UserFiles/File/40065182889.pdf
    • https://turbooto.vn/upload/files/fabodawukef.pdf
    • http://www.recetasyconsejos.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613578a29ad76---5427244842.pdf
    • http://lmalaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/kujesomofa.pdf
    • http://hnfhdc.com/UpLoadFile/2021090205295677468.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/ngfLrbzwjls/uplcv?utm_term=dragon+ball+z+kai+season+7
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000b0fd.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xB0FD 16792 bytes
font_01_sfnt_off0000c90f.bin
276852ceed8da308ad622761cc3761c59453c42b15c9d1fc35d90a30c2b33aa7
pdf-font-stream PDF embedded font (sfnt) at offset 0xC90F 16772 bytes
font_02_sfnt_off0000f395.bin
2bb59736f01e3649de4c44d186faf415614f327606ad43ed0f89758e1b8ffd6d
pdf-font-stream PDF embedded font (sfnt) at offset 0xF395 10528 bytes