Malicious PDF — malware analysis report

Static analysis result for SHA-256 4b19f4becab96c30…

MALICIOUS

PDF

77.9 KB Created: 2021-09-03 08:16:30 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 492d46441033490f42d87a99b8dd09f9 SHA-1: c13d40fdccd302192ff82ed4faccf1ebd2d61099 SHA-256: 4b19f4becab96c30c59554f724cb5420d67ede332ae09d062010d9c07bac54af
96 Risk Score

Malware Insights

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

The PDF file contains a large number of external links, many of which point to compromised WordPress sites. The ML classifier strongly indicated maliciousness, and the link farm structure suggests an attempt to lure users to potentially malicious websites. No scripts were extracted, and the document body was unreadable, so the primary attack vector appears to be the embedded URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

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://cructi.ru/uplcv?utm_term=agonista+y+antagonista+farmacologia+pdf PDF link annotation
    • http://innova-perila.ru/upload/files/gomibasojunuwikowenebor.pdfIn PDF document text
    • https://superpart.com/files/wajebifagulologibavupos.pdfIn PDF document text
    • https://autosaloncenter.com/uploads/file/zafuzezigu.pdfIn PDF document text
    • http://saokienviet.com/uploads/image/files/28381482929.pdfIn PDF document text
    • https://mudateconmigo.cl/wp-content/plugins/super-forms/uploads/php/files/1cfdc1852eaa04b73560387226de190b/94745759619.pdfIn PDF document text
    • https://mytalk7.com/_UploadFile/Images/file/rudefufo.pdfIn PDF document text
    • http://amako-ra.com/wp-content/plugins/super-forms/uploads/php/files/0874d8ea6fce6937844025da7807f8e9/paxatofofiwajetemexaz.pdfIn PDF document text
    • https://bluetact.com/locktactyuma/userfiles/file/16055436327.pdfIn PDF document text
    • http://prodesign31.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160a534ab34993---82937586319.pdfIn PDF document text
    • https://adbetelparaguay.com/wp-content/plugins/super-forms/uploads/php/files/4ab172d9748f096b13d312e8b44a8ea4/gewilimivuxe.pdfIn PDF document text
    • http://iccj.jp/images/uploads/fckeditor/file/lekob.pdfIn PDF document text
    • https://sogelec-eng.com/files/ckfinder/files/78735492736.pdfIn PDF document text
    • http://villabrown.it/userfiles/files/borexasaxotobalurufamarak.pdfIn PDF document text
    • https://kuechentreff-schmid.de/wp-content/plugins/super-forms/uploads/php/files/q5cqup0hee4ei1ursvofi40dce/33331112710.pdfIn PDF document text
    • https://ohligschlaeger-berger.de/wp-content/plugins/formcraft/file-upload/server/content/files/16109a9f7ea229---lemetezalidofewali.pdfIn PDF document text
    • https://ahi.com.ua/wp-content/plugins/super-forms/uploads/php/files/c896716aa1add367032f4c6019113058/fijuji.pdfIn PDF document text
    • https://www.kiteschule-kiel.de/wp-content/plugins/formcraft/file-upload/server/content/files/160d8d57c5a268---57092763639.pdfIn PDF document text
    • http://gangwonbnb.com/FileData/ckfinder/files/20210725_681B6A5AE817302E.pdfIn PDF document text
    • http://duythuc-bearing.vn/uploads/userfiles/file/21832273192.pdfIn PDF document text
    • http://www.siposferenc.hu/html/tirusotatiwalejad.pdfIn PDF document text
    • https://www.alongsideasia.com/wp-content/plugins/super-forms/uploads/php/files/b963b34fd35ddddb97fe916d8ac8e3b2/virefotosasedopirete.pdfIn PDF document text
    • https://vallejardin.com/wp-content/plugins/super-forms/uploads/php/files/58afc2b6f98ae1f593619c82c71832aa/rumuteduxexebitume.pdfIn PDF document text
    • http://autoshiftbid.com/fckeditor/userfiles/file/86438374672.pdfIn PDF document text
    • http://www.alfainstal.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160f983bcec7a2---jurukitenogiraxiwuki.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_off0000cb7b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCB7B 10928 bytes
SHA-256: b29d850ac900890d448127d2563d4c61df48b12c558b1083d6782405d8683781
font_01_sfnt_off0000e4a6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE4A6 18028 bytes
SHA-256: 8d911a1066ef7badcec11b2191c3624c02b4ebb844390f4e16dbd59ab2d8a480
font_02_sfnt_off000111f4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x111F4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1