Malicious PDF — malware analysis report

Static analysis result for SHA-256 f8a7fa420e70fc89…

MALICIOUS

PDF

91.4 KB Created: 2021-09-08 18:13:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 69d9b352cc894c53b19816bcfd6a12cf SHA-1: 76adb2ec796007c457d6156a2a672357685edbc5 SHA-256: f8a7fa420e70fc8919f118a159538fac09720017f620f15f7e2e1506f924d97e
96 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to other PDF files hosted on various domains. Several heuristics indicate this is a link farm, with some URLs pointing to compromised WordPress upload directories. The ML classifier strongly suggests maliciousness, likely due to the distribution of links and potential for SEO abuse or further payload delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9988

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://wastran.ru/uplcv?utm_term=grade+8+history+exam+papers+and+memos+pdf PDF link annotation
    • https://varbackaforskola.se/ckfinder/userfiles/files/fekadusagajazafofudijoro.pdfIn PDF document text
    • http://www.halpellet.hu/userfiles/files/buwexo.pdfIn PDF document text
    • http://architetturaurbanistica.it/userfiles/files/57752376733.pdfIn PDF document text
    • http://yigang-lin.com/uploads/files/202109081130111525.pdfIn PDF document text
    • http://alrabbanoilandgas.com/file/files/15288658062.pdfIn PDF document text
    • http://conservationenergy.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f87588e011---31763057700.pdfIn PDF document text
    • https://iieng.org/editor/ckfinder/userfiles/files/43459940756.pdfIn PDF document text
    • http://christopherspubandgrille.com/userfiles/files/23384141901.pdfIn PDF document text
    • http://jyjwqj.com/uploadfile/file///2021090806325453.pdfIn PDF document text
    • http://bfr-bialapodlaska.pl/userfiles/file/lojumukaxodexaludipira.pdfIn PDF document text
    • http://neilreardon.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/41021176321.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/161309fad03a4d---domutev.pdfIn PDF document text
    • http://hawaiianhunareiki.it/file/zujurudotiporeduz.pdfIn PDF document text
    • https://omnistopbollards.com/application/third_party/ckfinder/userfiles/files/magepuned.pdfIn PDF document text
    • http://capableapp.com/uploads/files/gusedomusokoboz.pdfIn PDF document text
    • https://loppisidjupdalen.se/images/uploaded/file/44197454505.pdfIn PDF document text
    • http://chinalabware.ru/d/files/42692646243.pdfIn PDF document text
    • https://rebates.forex/wp-content/plugins/super-forms/uploads/php/files/v6k1mg25a4274vg5rmq08o3rr6/7576568323.pdfIn PDF document text
    • https://webhostmurah.com/wp-content/plugins/formcraft/file-upload/server/content/files/16133ab36be4aa---32087669022.pdfIn PDF document text
    • http://francescofesta.it/userfiles/files/29072545888.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_off0000fdd8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFDD8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000115ef.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x115EF 11180 bytes
SHA-256: 69a6a4756aefc8345f8f99a30e4c8bc5e82af0be42039b5c7791b300405f7173
font_02_sfnt_off00013000.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13000 18144 bytes
SHA-256: 5177e7f5861b5db9f2547992395815e2ec8ae1462c836f25ab53da15627ecb89