Malicious PDF — malware analysis report

Static analysis result for SHA-256 21092a6c80ed0c4b…

MALICIOUS

PDF

85.0 KB Created: 2021-09-15 19:45:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 44d28b14e9b6d19a35348f7842f7de35 SHA-1: 56fd131e7b778c8683bd8679859e004e4ea55bea SHA-256: 21092a6c80ed0c4b14cb3653978b33238727e08b41e85e9b6bff800b5f65eb45
156 Risk Score

Malware Insights

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

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate the document functions as a link farm, directing users to multiple compromised or disposable hosting sites. The presence of numerous URLs, many pointing to PDF files hosted on potentially compromised WordPress sites, strongly suggests an attempt to distribute further malicious content or conduct phishing operations.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://deesudcoolingtower.com/userfiles/file/20388922564.pdf In PDF document text
    • http://kisito.com/userfiles/file/kuvajuwejuzoba.pdfIn PDF document text
    • https://gangwontaxi.com/FileData/ckfinder/files/20210909_718463AA4CA5E58A.pdfIn PDF document text
    • http://www.oknookna.pl/wp-content/plugins/formcraft/file-upload/server/content/files/16137e07a6a6ec---7077181943.pdfIn PDF document text
    • http://capitolmetrophysicaltherapy.com/files/files/juxaf.pdfIn PDF document text
    • https://unitytradefze.com/ckfinder/userfiles/files/jurugajudesofofubenepa.pdfIn PDF document text
    • https://www.businesswatchguardingservices.co.uk/wp-content/plugins/super-forms/uploads/php/files/u4kb6hfhdeuh8es63ugohcleph/ziredapun.pdfIn PDF document text
    • http://recit-de-vie.fr/userfiles/file/55300652990.pdfIn PDF document text
    • https://dhesient.com/media/kumin.pdfIn PDF document text
    • http://bayernglobal.de/userVZ/file/67552809158.pdfIn PDF document text
    • http://tuzvedo.hu/elemek/file/sifiwazudugitasuvax.pdfIn PDF document text
    • http://wooshin.kr/uploaded/file/4258136356137265f95b8f.pdfIn PDF document text
    • http://fairway.cc/images/blog/file/18446610077.pdfIn PDF document text
    • https://icon-studios.com/userfiles/file/wefapepogiludo.pdfIn PDF document text
    • http://parkwestresidences.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613580f7bae3d---wugifasajigaku.pdfIn PDF document text
    • http://ipceurope.com/assets/file/95292067293.pdfIn PDF document text
    • http://www.ibadirect.com/wp-content/plugins/formcraft/file-upload/server/content/files/16138f2567dead---pukonadutujidum.pdfIn PDF document text
    • http://asea-admin.com/_userfiles/file/20210907115126.pdfIn PDF document text
    • http://bandenplaats.nl/cmsimages/file/zumazizolozi.pdfIn PDF document text
    • https://aitalk.vn/upload/files/sedogukux.pdfIn PDF document text
    • http://werkkledingverkoop.nl/images/docman/files/80249314637.pdfIn PDF document text
    • https://u15.ch/ckfinder/userfiles/files/webubokufage.pdfIn PDF document text
    • https://korankertas.com/contents/files/galozugupivizakafobaden.pdfIn PDF document text
    • http://luatsugiadinhviet.com/upload/ck/files/vaburuwunonoxukesilojado.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1xuhb7AK25c/uplcv?utm_term=windows+7+ultimate+loaderPDF 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_off0000e695.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE695 10636 bytes
SHA-256: f411b515bee4a2cf4d9e05ca4c6b3061e012155e5806c04b296e5cebfc395d84
font_01_sfnt_off0000fefe.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFEFE 18384 bytes
SHA-256: ab24b74480f62e8d42c4d1410b71f0d11b29a187c9879d6c0674943e4e68efa4
font_02_sfnt_off00012e76.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12E76 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1