Malicious PDF — malware analysis report

Static analysis result for SHA-256 7c4e51e21c5f2456…

MALICIOUS

PDF

86.8 KB Created: 2021-09-17 06:25:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 456e06ce8755a2af31b5e3ca76383990 SHA-1: 4280e35dece7499e6ed0124c52e782312b14a845 SHA-256: 7c4e51e21c5f24569ffc86d3b70ca1765a2b77084777c5d73b7bee8d974ffc9b
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file contains numerous external URLs, many of which are hosted on compromised or disposable domains, indicating a link farm or SEO manipulation tactic. The ML classifier strongly flagged this PDF as malicious. While no scripts were directly extracted, the nature of the URLs suggests the PDF is designed to redirect users to potentially harmful content or further stages of an attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://krisoc.ru/uplcv?utm_term=best+android+app+player+for+pc PDF link annotation
    • http://mitsubishilongbien.vn/images/ckeditor/files/2572748089.pdfIn PDF document text
    • https://superpackeg.com/userfiles/file/zeromiviwupozaket.pdfIn PDF document text
    • http://nakakinpump.kr/fckeditor/upload/file/jofet.pdfIn PDF document text
    • http://nhatrangpalace.vn/app/webroot/upload/files/vigusisegaxit.pdfIn PDF document text
    • http://khangvietdn.com/uploads/file/wovajiniwagujabepus.pdfIn PDF document text
    • https://minipowerpack.net/upload/files/43521367007.pdfIn PDF document text
    • http://uteambio.com/upload/files/84727122621.pdfIn PDF document text
    • https://gogreenonline.net/userfiles/image/fckeditor/file/gubisisopizexaroket.pdfIn PDF document text
    • http://www.mvdisposal.com/wp-content/plugins/formcraft/file-upload/server/content/files/161329edb62da6---36841463525.pdfIn PDF document text
    • http://belean.pl/userfiles/file/leramoburek.pdfIn PDF document text
    • http://kronospan-mofa.hu/editor_up/tomirevonisariluk.pdfIn PDF document text
    • https://www.taxikladis.gr/wp-content/plugins/formcraft/file-upload/server/content/files/16143331dabfd6---76290547660.pdfIn PDF document text
    • https://matricula.arendic.cl/files/lewenasizupedu.pdfIn PDF document text
    • http://www.rannatennis.ee/data/upfiles/files/11855844941.pdfIn PDF document text
    • https://gsm.company/ckfinder/userfiles/files/setoponalen.pdfIn PDF document text
    • https://renewone.de/files/dofaruzoworaripozi.pdfIn PDF document text
    • https://sk-developers.com/wp-content/plugins/formcraft/file-upload/server/content/files/16138c8219a567---deloraropaxeninijag.pdfIn PDF document text
    • http://como.gattinonimondodivacanze.it/themes/userfiles/files/48736421285.pdfIn PDF document text
    • http://chayka-svg.ru/files/83733238166.pdfIn PDF document text
    • https://istruttorecinofilo.it/userfiles/file/xaxasokida.pdfIn PDF document text
    • http://consade.com/userfiles/file/wivekavu.pdfIn PDF document text
    • https://implantologie-deva.ro/app/webroot/files/userfiles/files/vuxavowikusem.pdfIn PDF document text
    • http://yunnanyingxiang.com/ckfinder/userfiles/files/12028302472.pdfIn PDF document text
    • http://sangiorgioautoservizi.com/userfiles/files/23081018063.pdfIn PDF document text
    • http://synerfreight.com/syner_upload/images/files/22492734260.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_off0000ef1f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF1F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010731.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10731 17332 bytes
SHA-256: ef104fb3fe287c5326abc3770755015d3243e907c512eed0e9e6317a75d36ca7
font_02_sfnt_off00013438.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13438 10780 bytes
SHA-256: 9e40f16eaf890c82f308034e83d333bac4ae36f4c39a6e688a562d52ebe48959