Malicious PDF — malware analysis report

Static analysis result for SHA-256 4ec656ebae88fba5…

MALICIOUS

PDF

79.6 KB Created: 2021-09-06 02:35:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: f8c1bae5adbfa12759c994d7b4b39eba SHA-1: 06e668f6e18100062aeffea4271fcc84cd64d68a SHA-256: 4ec656ebae88fba5d90523721f6bd43d4c88d162428978bd638e7db3b5dac8a9
104 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript and a large number of external URIs, many of which point to compromised CMS uploads or disposable hosting, indicating a link farm designed to distribute malicious content. The ML classifier strongly flagged this PDF as malicious. The embedded JavaScript likely facilitates the redirection or execution of further malicious actions.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 6

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://infrive.ru/uplcv?utm_term=adding+and+subtracting+integers+worksheet+with+answers
    • https://k9-warrior.com/wp-content/plugins/super-forms/uploads/php/files/1ocmopqqtqjj1pjj0gvv9es8ld/jegitagene.pdf
    • https://jdbailbonds.com/wp-content/plugins/super-forms/uploads/php/files/2a833b7dbb4117bfea2c130a86b481fd/rarelen.pdf
    • https://contabil-fiscal.ro/mm/file/85640180600.pdf
    • https://www.colegiodesafio.net/home/wp-content/plugins/formcraft/file-upload/server/content/files/16095b703367c8---64701042574.pdf
    • http://www.domplit2006.ru/ckfinder/userfiles/files/vojazir.pdf
    • https://xlux.vn/wp-content/plugins/super-forms/uploads/php/files/ad46fsqo28b8h0v1joatt3glgg/nevasinoluneleb.pdf
    • https://www.diktu.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a7580f84345---69849502127.pdf
    • https://u15.ch/ckfinder/userfiles/files/nuxaxafub.pdf
    • https://velvetskin.pl/wp-content/plugins/super-forms/uploads/php/files/7ed4d4088eb530f825a820f56612dc23/selukefokiriwonezovad.pdf
    • http://kurskodkb.ru/page_edit/_samples/userfiles/files/dobuwigev.pdf
    • https://harpethvalleypto.org/wp-content/plugins/super-forms/uploads/php/files/8f6c32ddf8d4e049a3dbd2d6e3dd1525/xizexapozo.pdf
    • http://littlepearlspublishing.in/data/eimages/file/68942879632.pdf
    • http://gshosnab.ru/userfiles/file/29050502503.pdf
    • https://www.hed-endo.hr/wp-content/plugins/formcraft/file-upload/server/content/files/160adacd2d60a4---69927186023.pdf
    • http://bjallstar.com/upload/file/8440489241.pdf
    • https://dacola.com/upload/files/47459974278.pdf
    • http://sh8ke.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ac4c46b7321---28597764341.pdf
    • https://www.histoiresdegroupes.com/wp-content/plugins/formcraft/file-upload/server/content/files/160caa6c49d283---16086673901.pdf
    • http://accessprecision.com/userfiles/file/dotejosu.pdf
    • https://baileyelectrical.services/wp-content/plugins/super-forms/uploads/php/files/ooqbb5ohneh4qhv1vh6clcbmjk/xibumizilawidulo.pdf
    • http://cobe-ing.it/userfiles/files/gawifusosagojajes.pdf
    • https://unicorn.mn/js/ckfinder/userfiles/files/waxowopagubilekexatuzijis.pdf
    • http://cka-shiba.com/ckfinder/userfiles/files/80352086081.pdf
    • https://nikoljski.com/ckfinder/userfiles/files/gepazofere.pdf
    • https://baconbites.com/wp-content/plugins/super-forms/uploads/php/files/2gmiafdu35vq79rj4re8kl4bp6/10987915771.pdf
    • 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_off0000cd29.bin
d08b0c8714da3196a5e4dec7e3961636f7424a29d4b18be03ef2612789766557
pdf-font-stream PDF embedded font (sfnt) at offset 0xCD29 18824 bytes
font_01_sfnt_off0000fe7d.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xFE7D 16792 bytes
font_02_sfnt_off00011694.bin
435e7c786b3666c5904bbee489d2a18516ecf18ee6067d1f0d6fc8d98fc3938c
pdf-font-stream PDF embedded font (sfnt) at offset 0x11694 11000 bytes