Malicious PDF — malware analysis report

Static analysis result for SHA-256 68b91089572d3da2…

MALICIOUS

PDF

73.6 KB Created: 2021-09-10 08:21:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 4a72dd80e1b9df8ddc4976ae5de69166 SHA-1: efbad78c05f4c1ab199c34ff25a29f06e3f7d7ab SHA-256: 68b91089572d3da2478a8be3df4299259b85baae56b470feb754f5b46a37b8f6
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file contains numerous embedded URLs that point to other PDF files hosted on various domains. The heuristic 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' indicates that some of these links point to compromised WordPress upload storage, suggesting a distribution mechanism for malicious content. The ML classifier also flagged this PDF as malicious with high confidence.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9971

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://estudiowebcolombia.com/ckfinder/userfiles/files/xepurevowuk.pdf In PDF document text
    • https://dedywiredja.com/wp-content/plugins/formcraft/file-upload/server/content/files/16134ce62ab9f3---pusojuveketasutaxa.pdfIn PDF document text
    • https://advance-pack.com/editor_upload/file/rodarosotoxi.pdfIn PDF document text
    • https://makenie.com/upload/files/18311497462.pdfIn PDF document text
    • http://outspokenholland.com/userfiles/fckFile/20210905214923.pdfIn PDF document text
    • http://musthighschool.mn/ckfinder/userfiles/files/62740432680.pdfIn PDF document text
    • https://hamayeshniroo.com/shop/file/72758062644.pdfIn PDF document text
    • https://eclearusa.com/images/file/korimilas.pdfIn PDF document text
    • https://civilkontroll.hu/uploads/file/vofaziwatutawanaraxe.pdfIn PDF document text
    • https://aokman-drive.com/d/files/fimikejebidaluvabimope.pdfIn PDF document text
    • https://stakeoutllc.com/wp-content/plugins/super-forms/uploads/php/files/514724dfd864436f56037cae2cc9693d/67341221015.pdfIn PDF document text
    • http://bualuang101.com/backoffice/upload/files/teviparapupipevelojup.pdfIn PDF document text
    • http://www.europesolidaire.eu/userfiles/files/sazujawatopuxitupedoxifiw.pdfIn PDF document text
    • https://www.bouldersudbury.org/wp-content/plugins/formcraft/file-upload/server/content/files/16134cb9897d3f---kiwotefawamadodeti.pdfIn PDF document text
    • https://www.kiteschule-eckernfoerde.de/wp-content/plugins/formcraft/file-upload/server/content/files/16134d7e107f16---nepuvasol.pdfIn PDF document text
    • http://perchegouet.com/ckfinder/userfiles/files/93210848.pdfIn PDF document text
    • http://kvrhousing.com/uploads/46287136673.pdfIn PDF document text
    • http://leaguengn.com/userfiles/file///biduvefikarefeduki.pdfIn PDF document text
    • https://kitapkapla.com/upload/ckfinder/files/juxejawerogozo.pdfIn PDF document text
    • http://agedwedfjtj.pretty-match.com/upload/files/kibebiwerow.pdfIn PDF document text
    • http://kfnmsz.com/upfolder/e/files/20210909025931.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=how+to+turn+developer+options+onPDF 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_off0000be90.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBE90 16476 bytes
SHA-256: 0d430ae8e03281169f4499cfc0ddcbaa6686750fff318282c560707575ee64b1
font_01_sfnt_off0000e90b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE90B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010122.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10122 10468 bytes
SHA-256: ae54619339fdb71d185c6ccc889a8bdac6d426d24dead86f77dfc7df5c06d065