Malicious PDF — malware analysis report

Static analysis result for SHA-256 cd35c526bc28aa67…

MALICIOUS

PDF

78.2 KB Created: 2021-09-08 19:17:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: a21afaa8f0b40ff5b501ef9667b2e3f5 SHA-1: 94365a61d1fb249d3480aca2c5d6acc0dd07ced8 SHA-256: cd35c526bc28aa67cbc963c14af5dc3e7b25c5e889ba10e3f99afe54913f59e8
96 Risk Score

Malware Insights

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

The PDF contains numerous external URIs and link farms pointing to other PDF files hosted on various domains, some of which appear to be compromised CMS uploads. The ML classifier strongly indicated maliciousness, and the structure suggests a deliberate effort to obscure the final destination of the links, likely to distribute malicious content or conduct phishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://pistant.ru/uplcv?utm_term=typhonian+order+pdf PDF link annotation
    • https://stopserv.ru/files/file/69751927023.pdfIn PDF document text
    • https://cursosadistanciayonline.com/medios/files/89896451107.pdfIn PDF document text
    • http://hebammenglueck.de/ckfinder/userfiles/files/47239918366.pdfIn PDF document text
    • http://meghdoothsuzuki.com/uploads/62805712847.pdfIn PDF document text
    • https://musikkursus.dk/userfiles/file/54626528865.pdfIn PDF document text
    • http://proficlim.ru/public/userfiles/file/savikajobuku.pdfIn PDF document text
    • https://ncfouting.com/wp-content/plugins/formcraft/file-upload/server/content/files/161376b58b4660---10977688556.pdfIn PDF document text
    • http://terapie-psi.ro/wp-content/plugins/formcraft/file-upload/server/content/files/16136250d90af6---fijisujunajigifugave.pdfIn PDF document text
    • http://metabolit-plus.ru/files/file/ledatufeledajapinuduk.pdfIn PDF document text
    • http://marchmont.ru/imgs/file/19415659459.pdfIn PDF document text
    • https://predial-rua-nova.pt/056-CovadaLua/images-editor/file/47313684880.pdfIn PDF document text
    • https://adtw1.com/ckfinder/userfiles/files/donerefegekabowaxudisel.pdfIn PDF document text
    • https://personalloan2u.com/wp-content/plugins/super-forms/uploads/php/files/66fa1802a44f4988a7e25a744a7361a1/gazerenomaveb.pdfIn PDF document text
    • https://davnosti.ru/upload/90475153223.pdfIn PDF document text
    • http://erfaspot.com/resimler/files/lorulag.pdfIn PDF document text
    • https://termofriz.rs/files/45853492238.pdfIn PDF document text
    • http://quinta.cl/upload/files/99716364321.pdfIn PDF document text
    • https://emotionalgift.com/ckfinder/userfiles/files/buvivuzitexesas.pdfIn PDF document text
    • http://sparan-art.ru/ckfinder/userfiles/files/74827612306.pdfIn PDF document text
    • http://pnc21.com/files/fckeditor/file/18481132076137b8c09739e.pdfIn PDF document text
    • https://f1com.ge/wp-content/plugins/super-forms/uploads/php/files/518b6a8409358a763f47d9fcbde23905/51153550094.pdfIn PDF document text
    • http://thuduchouse.vn/pics/file/fasopigudenofixewazafufe.pdfIn PDF document text
    • http://abwninemile.com/uploads/files/pagiledub.pdfIn PDF document text
    • http://lamelove-zakryti.cz/userfiles/file/gosexulowoba.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_off0000ccc0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCCC0 17988 bytes
SHA-256: 290e60043b531aeedd64ee8c13fb8e21c8b68cc9776d42b428a114128b0a318e
font_01_sfnt_off0000fbd2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFBD2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000113e9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x113E9 10360 bytes
SHA-256: 160d6396cb0f503ae5cc7e447547ee603c88fd7c386f2af7664f139647642b34