Malicious PDF — malware analysis report

Static analysis result for SHA-256 4afc525b378a4c1a…

MALICIOUS

PDF

85.6 KB Created: 2021-09-07 23:36:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 0ef0256b2c9cc3aa7fd360c3eae55337 SHA-1: 5b035200b8387ce123b13cbfd630b889c5e6b062 SHA-256: 4afc525b378a4c1aee588de1dd1337640e5e989621fefd47b93634dfec3c800b
104 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript and numerous external URIs, many of which point to compromised CMS upload directories or are part of link farms. The ML classifier strongly indicates maliciousness. The embedded JavaScript likely facilitates the redirection to these malicious URLs, which are designed to host further malicious content or phishing pages.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9912

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://krisoc.ru/uplcv?utm_term=kaplan+sat+subject+test+literature+pdf PDF link annotation
    • http://clainvest.pl/userfiles/file/34800790649.pdfIn PDF document text
    • https://corumosmanlimakina.com/js/ckfinder/userfiles/files/55538839774.pdfIn PDF document text
    • http://platcometals.com/images/file/gobivo.pdfIn PDF document text
    • http://dentherapia.hu/files/file/fizifuximipu.pdfIn PDF document text
    • http://finsura-lifedirect.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1606d0faa34717---kogetisumubivogezumele.pdfIn PDF document text
    • https://svetpoznaniyaonline.ru/wp-content/plugins/super-forms/uploads/php/files/da7309bffeeed44b5eb3f109542c2307/98417713762.pdfIn PDF document text
    • https://copab.tn/216mag.svn/uploads/files/8330131866.pdfIn PDF document text
    • https://learn-atdi.com/uploads/files/79590284412.pdfIn PDF document text
    • https://fiambreszav.com/wp-content/plugins/super-forms/uploads/php/files/17b1ab6ff49e775c0e96596dcb03dddf/sajokovujogikusifor.pdfIn PDF document text
    • http://www.radanhorse.com/resource/files/69879184483.pdfIn PDF document text
    • http://bjsprt.com/uploadfile/file///2021060914132861.pdfIn PDF document text
    • http://interel-rus.ru/test/sites/default/files/file/54777250034.pdfIn PDF document text
    • http://czpohledavky.cz/userfiles/files/nedajumerokelubinipo.pdfIn PDF document text
    • http://immobilieninvestors.eu/userfiles/file/55930084759.pdfIn PDF document text
    • http://yjccnc.com/upload/files/vukakufamukasisodedirafut.pdfIn PDF document text
    • http://mujuerp.com/uploads/ckeditor/files/20210616084126.pdfIn PDF document text
    • http://syarmarka.ru/userfiles/files/maneroxuzegis.pdfIn PDF document text
    • https://www.couleurs-et-jardin.fr/wp-content/plugins/formcraft/file-upload/server/content/files/16094593302e75---giropelufujomevaguweb.pdfIn PDF document text
    • http://chaukitchen.com/uploads/files/mofasex.pdfIn PDF document text
    • https://edoxmarketing.com/wp-content/plugins/super-forms/uploads/php/files/t57bibn2b4it1u8ca4t7s92gun/sitadalapezisajeda.pdfIn PDF document text
    • http://dedanskecasinoer.dk/userfiles/file/kaxina.pdfIn PDF document text
    • https://birudongker.com/contents//files/lunilalun.pdfIn PDF document text
    • http://putzlappenborner.at/editor_up/34217128715.pdfIn PDF document text
    • https://rowanmkt.com/Uploads/ckfinder/userfiles/files/nowal.pdfIn PDF document text
    • https://www.burit.net/wp-content/plugins/formcraft/file-upload/server/content/files/160a278c7459e9---girudaveb.pdfIn PDF document text
    • http://mebco.ru/images/file/88399040864.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_off0000e60b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE60B 10856 bytes
SHA-256: 833c721f6a2d14a9efd79f43309480e846ca7d8c362ddc3d3308cd8d77bdff39
font_01_sfnt_off0000fef6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFEF6 18788 bytes
SHA-256: e988a95c6d63ab63afa1030bedd07c1951434321ddef5c41dd047ef724a4846d
font_02_sfnt_off00012fc2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12FC2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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