Malicious PDF — malware analysis report

Static analysis result for SHA-256 e836571162cc300f…

MALICIOUS

PDF

80.5 KB Created: 2021-09-19 00:15:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: f1451ef8a690671bc7db16d44e4da3fe SHA-1: ad3a327726dc43951c1b79ecd7acadd656d1265e SHA-256: e836571162cc300fe72249f60e4426eb5b07cafd6c047e359c98c16b3ba8fb41
164 Risk Score

Malware Insights

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

The PDF contains numerous external links, many pointing to PDFs hosted on compromised CMS platforms or disposable domains, indicative of a link farm. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for SEO poisoning or to distribute further malicious content. The presence of a 'download' button heuristic further supports a user-luring workflow.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 7

  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://catamma.ru/uplcv?utm_term=ringtone+sounds+for+android PDF link annotation
    • https://xtrafitcoaching.com/www/images/files/talajegosoxujusanewevet.pdfIn PDF document text
    • http://qwerty.pl/_data/file/pesaraxejezumokerekog.pdfIn PDF document text
    • http://korea-seals.com/ckfinder/userfiles/files/xabitusowovoturur.pdfIn PDF document text
    • https://confetti-seasons.ru/upload/files/56733078307.pdfIn PDF document text
    • http://qkmedica.com/uploads/userfiles/file/xoromiwepesaromelirexev.pdfIn PDF document text
    • https://xenang-mitsubishi.com/fckupload/file/67471448128.pdfIn PDF document text
    • http://laihoawedding.com/app/webroot/upload/files/ninuwaxozusofutesaxubuzi.pdfIn PDF document text
    • https://censcakmu.org/board/file/files/18040424395.pdfIn PDF document text
    • https://xn--fct8ml6mwue.tw/uploads/files/vazip.pdfIn PDF document text
    • http://thamcohoaian.com/webroot/img/files/dovuzipokapigekepat.pdfIn PDF document text
    • https://ppntassone.it/dati/upload/file/gatepiniduro.pdfIn PDF document text
    • http://ciccioinpentola.com/userfiles/files/jipalezekijoj.pdfIn PDF document text
    • http://ozhelalikram.de/resimler/files/puxonufasomije.pdfIn PDF document text
    • http://www.qookspot.kitchen/wp-content/plugins/formcraft/file-upload/server/content/files/16134e8128b3f7---52679502217.pdfIn PDF document text
    • http://naturestuff.nl/siteimages/file/bulavodiponinalumogige.pdfIn PDF document text
    • http://rafaelokazakov.com/file/26964055422.pdfIn PDF document text
    • http://www.vitrierbxl.be/wp-content/plugins/formcraft/file-upload/server/content/files/16133e92a28a8a---nalupobuzabijubusot.pdfIn PDF document text
    • https://areshin.ru/wp-content/plugins/super-forms/uploads/php/files/538f978151f7f577813ded57f767d107/zudenuvi.pdfIn PDF document text
    • http://www.immiflex.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139f56d254ef---74728618937.pdfIn PDF document text
    • http://abapaposentados.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16135af2743351---sipumevo.pdfIn PDF document text
    • https://intersensor.ro/v2011/Files/fck_upload/file/39503140475.pdfIn PDF document text
    • http://sin-hua.org/userfiles/lobinap.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_off0000d7d2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD7D2 17128 bytes
SHA-256: d7a8f512df56fa76bead1bf1246a454d132ffca1169d93e825e9850ed072258b
font_01_sfnt_off0001041e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1041E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011c35.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11C35 10628 bytes
SHA-256: db7c6dad30d6db3e85d900367db7067c9ca731d9f1830471229547088b6911d1

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