Malicious PDF — malware analysis report

Static analysis result for SHA-256 b1e5c81aade176bf…

MALICIOUS

PDF

87.0 KB Created: 2021-09-18 20:18:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 2c8de4f060916d3d3e45d36d0833f501 SHA-1: ee0bb4699a28e9f8c4f6c21b1629ed5267fbb2b0 SHA-256: b1e5c81aade176bf5d2e49f4028a623136bd3b4c9b1912ee5f617af1549ef04c
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF contains a large number of embedded URLs, many of which point to other PDF files hosted on various domains. Several heuristics indicate this is a link farm, with some links pointing to compromised CMS uploads. The ML classifier strongly suggests maliciousness, likely due to the distribution of these links.

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 http://spbmedax.ru/sites/default/files/uploads/17615916561.pdf In PDF document text
    • http://www.laterveer-biesenbeek.nl/ckfinder/userfiles/files/54645797246.pdfIn PDF document text
    • http://www.520amis.com/upload/files/23624473030.pdfIn PDF document text
    • https://study-go.info/wp-content/plugins/super-forms/uploads/php/files/adca23ba91e239619b0031870a4d197d/firomasinud.pdfIn PDF document text
    • http://orderkiwicafe.com/uploads/files/52998479268.pdfIn PDF document text
    • http://kd-council.com/upfile/files/28676301336.pdfIn PDF document text
    • https://fundacjanadzieja.com/images/wyswig_images/file/10439252872.pdfIn PDF document text
    • http://devison-matras.com/upload/file/fabidiputa.pdfIn PDF document text
    • http://partnercable.hu/files/17847524669.pdfIn PDF document text
    • http://murzilka.biz/images/uploads/file/bivujizasobinobodir.pdfIn PDF document text
    • http://tourister.kr/userfiles/file/27839281580.pdfIn PDF document text
    • https://www.tifdip.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613e7c6dadee5---joduzupamulekuto.pdfIn PDF document text
    • http://icmasistemas.com/userfiles/files/28443767293.pdfIn PDF document text
    • http://taixingchem.com/uploadfile/file/20210909192621345.pdfIn PDF document text
    • http://bigyikesmedia.com/home/xtremweb/public_html/consultinstitute/web/upload/files/fifosabomoleso.pdfIn PDF document text
    • http://draftingfloorplan.com/ckfinder/userfiles/files/81768450207.pdfIn PDF document text
    • https://adiwirawanbali.com/wp-content/plugins/super-forms/uploads/php/files/8abf37cfb73a9d9a1b4a8b75ec40bf8b/sijezasivetakubazurota.pdfIn PDF document text
    • http://tbff-bygg.se/img/files/kakuwafate.pdfIn PDF document text
    • http://baigeleather.com/userfiles/file/wuxorajavakekuwefazebasib.pdfIn PDF document text
    • https://granitabrasive.hu/editor_up/30892800213.pdfIn PDF document text
    • http://manu-transport.com/documents/file/posil.pdfIn PDF document text
    • https://hunglivet.com/uploads/files/202109081428479885.pdfIn PDF document text
    • http://paymentsbusiness.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1612f8e1f236b7---1351766184.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BkSY9tpko7c/uplcv?utm_term=letters+beginning+with+mPDF link annotation
    • 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_off0000efd0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEFD0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000107e2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x107E2 18780 bytes
SHA-256: 6b2f7950b0dd46ed26e364aee242c45f208d74a7d6d6dde7aef53c1440f01fe6
font_02_sfnt_off00013766.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13766 10412 bytes
SHA-256: afaf9df897c4cd36d9d5f7d9efc544efdcb398600666057cc7ce91c4395fadd5