Malicious PDF — malware analysis report

Static analysis result for SHA-256 a94d77c5590171e7…

MALICIOUS

PDF

86.9 KB Created: 2021-09-24 02:01:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 11e4438c5c36dadb94f0409f304e6bb3 SHA-1: fdcb38e212bc3c1b7ec18a0168f1ff78c22ede01 SHA-256: a94d77c5590171e77a7caa47a6430c6755977cdc80d117bfcb952436a9317815
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF document was identified as malicious by an ML classifier. It contains numerous embedded URLs, many pointing to compromised WordPress sites and disposable hosting, suggesting a link farm or redirection scheme. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, with no clear user-facing content. The presence of embedded URLs and the nature of the heuristics indicate an attempt to direct users to potentially malicious external resources.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

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://allytemp.ru/uplcv?utm_term=augmented+reality+using+android+studio PDF link annotation
    • http://careerhack.net/wp-content/plugins/formcraft/file-upload/server/content/files/16148513abe33b---51217104487.pdfIn PDF document text
    • http://fpole.ru/sadm_files/66394125153.pdfIn PDF document text
    • https://sailstudy.in/ckfinder/userfiles/files/14927650969.pdfIn PDF document text
    • http://logopeda-empatia.pl/content/file/vavaxufili.pdfIn PDF document text
    • http://fairway.cc/images/blog/file/tivisexutojexixevexabuzoz.pdfIn PDF document text
    • http://www.musicmaestrodiscos.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16140614f428ed---xejonesudukizujogovasukel.pdfIn PDF document text
    • http://paglialonga.it/userfiles/files/fozatavonizitujuxev.pdfIn PDF document text
    • http://www.commandinglife.com/wp-content/plugins/formcraft/file-upload/server/content/files/161314b3a92b05---jurasavugu.pdfIn PDF document text
    • https://fatheragneliti.com/wp-content/plugins/formcraft/file-upload/server/content/files/16135e68e3827f---8169842721.pdfIn PDF document text
    • https://alkhairi.co.uk/wp-content/plugins/super-forms/uploads/php/files/488aebba02d7253822ec2628e608ddab/vuwida.pdfIn PDF document text
    • http://www.movingintofreedom.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614cd19f1427e---45401714924.pdfIn PDF document text
    • http://miamiwars.pl/wp-content/plugins/super-forms/uploads/php/files/34382e50d2ecf10ef7b94721b32e728b/73762355717.pdfIn PDF document text
    • http://daiquangsico.com/img_duhoc/files/24020150174.pdfIn PDF document text
    • http://brbud.pl/userfiles/file/40340885697.pdfIn PDF document text
    • http://alphamarino.kz/images/news/file/5533242275.pdfIn PDF document text
    • https://indoshaolinkungfusociety.com/ckfinder/userfiles/files/20057892897.pdfIn PDF document text
    • http://xycrusher.com/d/files/nexewilapabapepirurubidu.pdfIn PDF document text
    • https://tootooair.com/FileData/ckfinder/files/20210917_1B96660FA4176304.pdfIn PDF document text
    • http://irollee.com/userfiles/file/84481411923.pdfIn PDF document text
    • https://longislandinvestmentadvisors.com/nini/userfiles/file/64752590605.pdfIn PDF document text
    • https://chambres-a-la-ferme-plouzelambre.fr/userfiles/file/8999030609.pdfIn PDF document text
    • http://rebizplus.com/userfiles/file/zokozogiwefijuvinuxe.pdfIn PDF document text
    • http://mptech.vn/ckfinder/userfiles/files/lifimuwexomugazunenatomev.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_off0000ee5a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE5A 17700 bytes
SHA-256: 65685e348aec13638653bcaabd79f9d361afaf9981bc7088e172db8161d77fef
font_01_sfnt_off00011d43.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11D43 10784 bytes
SHA-256: 09f2e5906234c1c5fc35deba76bc52481e542c5ff71064d546f5d24c6f1a452d
font_02_sfnt_off000135e9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x135E9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1