Malicious PDF — malware analysis report

Static analysis result for SHA-256 16b6c1fc4ec69916…

MALICIOUS

PDF

88.5 KB Created: 2021-06-27 21:44:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-20
MD5: 5e4810170a541309d51a65cdb12e9af5 SHA-1: 6fc64ca92cb4ebec0404c4217ba9ab7539c32a4c SHA-256: 16b6c1fc4ec6991600675d68ff8b3310aa1fb8d54e496d2f00d54f61fecfbccd
96 Risk Score

Malware Insights

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

The sample is a PDF document that contains a link farm pointing to multiple compromised WordPress sites and disposable domains. These links likely serve as a redirection mechanism to further malicious content or phishing pages. The ML classifier strongly indicated maliciousness, and the presence of numerous external links on potentially compromised infrastructure supports a campaign aimed at user redirection.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

Heuristics 5

  • 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://crysiq.ru/uplcv?utm_term=anaplasmosis+in+cow PDF link annotation
    • https://next-engineering.com/userfiles/files/16693927689.pdfIn PDF document text
    • https://www.okcfarmersmarket.com/wp-content/plugins/super-forms/uploads/php/files/0cf58a3e86dfa8fbf15450444fe77c9e/64563035470.pdfIn PDF document text
    • http://tragiaocolamsapa.com/userfiles/image/file/8847609501.pdfIn PDF document text
    • https://forkidsvietnam.vn/wp-content/plugins/super-forms/uploads/php/files/9iscat7be66dvjfcpe7hq2j376/90201171151.pdfIn PDF document text
    • https://betentour.com/sites/default/files/file/48658868451.pdfIn PDF document text
    • http://saamfactory.com/wp-content/plugins/super-forms/uploads/php/files/1db40952c5475b58a53ba19f24396bdb/xinumavafazapowudapas.pdfIn PDF document text
    • http://consulcongress.it/uploads/assets/file/44688027768.pdfIn PDF document text
    • http://sns.hu/_user/file/guvekubafis.pdfIn PDF document text
    • https://baconbites.com/wp-content/plugins/super-forms/uploads/php/files/0h07ur617aqclol9t402gnlbj5/75420779977.pdfIn PDF document text
    • http://teormech.ru/teormech/usrimg/file/54431919337.pdfIn PDF document text
    • http://vietsinphar.com/uploads/files/fuzujaxogaviwe.pdfIn PDF document text
    • https://www.cocochan.com.pk/wp-content/plugins/super-forms/uploads/php/files/7f53d60ae18a8c08e47259c68409e537/pofapolovowiwavefubuw.pdfIn PDF document text
    • http://lt101shop.com/userfiles/files/35947123969.pdfIn PDF document text
    • https://dedywiredja.com/wp-content/plugins/formcraft/file-upload/server/content/files/16085c35ac9398---33056390125.pdfIn PDF document text
    • http://botosani.ro/img/uploads/file/dabizoreripo.pdfIn PDF document text
    • https://www.couleurs-et-jardin.fr/wp-content/plugins/formcraft/file-upload/server/content/files/160ac17c9be5ac---67045803392.pdfIn PDF document text
    • https://surupaceanu.ro/ckfinder/userfiles/files/31407146003.pdfIn PDF document text
    • https://leicht-spb.ru/wp-content/plugins/super-forms/uploads/php/files/628f4fab6ffdb11f1915d65c6bf3e8c3/62050325883.pdfIn PDF document text
    • https://www.espymetcalf.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b731973c125---35508999351.pdfIn PDF document text
    • http://vyveva.eu/UserFiles/File/malidekujumumilukenoveje.pdfIn PDF document text
    • https://swift-tw.com/lcc/upload/files/37454453985.pdfIn PDF document text
    • https://fellowpeo.com/wp-content/plugins/super-forms/uploads/php/files/f0a75af5ec77d5cf193d810579489f35/luxuvakawi.pdfIn PDF document text
    • https://sidexsideaudio.com/wp-content/plugins/formcraft/file-upload/server/content/files/16090931271e2c---zuxezajuvafutavuzatuz.pdfIn PDF document text
    • https://creativesilhouettes.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1607780626b28a---jibekipimovudirosemobujig.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_off0000fb6e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFB6E 16332 bytes
SHA-256: dc8d6eebae248bd2d34d51a05443a89820ec6c0414ecf70c66e1cd524401efa9
font_01_sfnt_off000125b6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x125B6 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00013dcd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13DCD 10272 bytes
SHA-256: c223ddd1fafe60cd8b1b80f8ff972f0d9b30cc3d982f2a4eebf54bb23d731e4b