Malicious PDF — malware analysis report

Static analysis result for SHA-256 834b299cd8c2849c…

MALICIOUS

PDF

70.9 KB Created: 2021-09-18 10:26:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-22
MD5: 3fad9ac32e520efd2d2cf52629373cd0 SHA-1: 80731bbecce8bdcae81cf4ad5ef77cb9949244c2 SHA-256: 834b299cd8c2849cb87e7e85af5b29da35f42866c55be6ac39062e6e32a1f2b6
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ML classifiers and ClamAV as malicious, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm, with many URLs pointing to PDF files hosted on compromised CMS uploads and disposable domains. The primary purpose appears to be distributing further malicious content or phishing lures through these linked PDFs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://classoft.ro/userfiles/file/90679968158.pdf In PDF document text
    • http://portalinmobiliario24.com/uploades/fckeditorfile/lopijawizesif.pdfIn PDF document text
    • http://megatex-plast.ru/pub/file/26775403499.pdfIn PDF document text
    • http://shahgrp.com/uploads/lobasixexarumule.pdfIn PDF document text
    • https://www.dogandemir.av.tr/paketler/ckfinder/dosyalar/files/29684222133.pdfIn PDF document text
    • http://kingkady.cn/uploadfile/files/putup.pdfIn PDF document text
    • https://www.kiteschule-kiel.de/wp-content/plugins/formcraft/file-upload/server/content/files/16139c1aa4593c---jimakol.pdfIn PDF document text
    • http://mientaytourist.com/uploads/files/zobarosofodibovom.pdfIn PDF document text
    • http://abwlanham.com/uploads/files/10192161697.pdfIn PDF document text
    • https://www.opsclown.it/ckfinder/userfiles/files/79661669080.pdfIn PDF document text
    • http://belst.by/upload/file/50124802126.pdfIn PDF document text
    • https://charteriraq.ir/basefile/charteriraqir/files/zatisigetodalug.pdfIn PDF document text
    • http://www.guaitoli.eng.br/wp-content/plugins/formcraft/file-upload/server/content/files/1613862df8721c---zitasidi.pdfIn PDF document text
    • http://kerekagy.hu/UserFiles/file/defitutukep.pdfIn PDF document text
    • http://diadiemvui.com/upload/files/9512026849.pdfIn PDF document text
    • http://serviphony.com/tinymce/jscripts/tiny_mce/plugins/phpimage/phpimage/upload/images/file/jaxox.pdfIn PDF document text
    • http://wxmx.cn/upload/ckimg/files/202109081952019322.pdfIn PDF document text
    • http://petswithlove.com/cvsprojects/SSK/Source/2.0.0/images/files/88548209339.pdfIn PDF document text
    • https://puertoestereo.com/wp-content/plugins/super-forms/uploads/php/files/16o8eko18f54c65rgo0gt61s3i/sisib.pdfIn PDF document text
    • https://kme.pl/global/app/webroot/uploads/file/16318548936115.pdfIn PDF document text
    • https://mcq.bmtinhoc.vn/InteriorWeb/images/images_news/files/vosokakagi.pdfIn PDF document text
    • http://flemingdecal.com/uploads/assets/file/8755196632.pdfIn PDF document text
    • http://deeringbayrealestate.com/userfiles/files/15186332458.pdfIn PDF document text
    • https://tahitotfaluovodak.hu/ckfinder/userfiles/files/71284201605.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/A3Ryygt5BCM/uplcv?utm_term=touch+vpn+for+pc+apk+downloadPDF 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_off0000b799.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB799 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cfb0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCFB0 10532 bytes
SHA-256: ac0d4f3e965ffc4e909c526bc353760aa1355e2d6869649b3f823ecac5fcbf40
font_02_sfnt_off0000e7a9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE7A9 15124 bytes
SHA-256: 005bcef222707d72f26f942257d4949a285a2c850821125601e6bd112a3b12b2