Malicious PDF — malware analysis report

Static analysis result for SHA-256 3f351144dc9fbb91…

MALICIOUS

PDF

80.8 KB Created: 2021-09-12 16:27:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 31da5c74a031c5d1b59d0e4c93f9239d SHA-1: 1994c5fc1c9e0a5b0e397553438fc77551b32a34 SHA-256: 3f351144dc9fbb9142d9d1197cd8a035e793922733b5685f4cbb8355e1eb0095
156 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics as a link farm, with several URLs pointing to compromised CMS uploads and disposable hosting. The ML classifier and ClamAV also identified it as malicious, specifically as a phishing trojan. The document body is heavily obfuscated and appears to be generated content rather than user-readable text, reinforcing the malicious intent of directing users to external, potentially harmful, sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9972

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://osikovo.eu/webroot/img/content/files/15292036349.pdf In PDF document text
    • http://tareeapartment.com/user_img/files/11144701463.pdfIn PDF document text
    • https://bda.ch/ckfinder/userfiles/files/52435802847.pdfIn PDF document text
    • https://altstudio.be/app/webroot/uploads/file/13945325586.pdfIn PDF document text
    • https://uslugiinzynierskie.eu/eurostyl/photos/file/69071332249.pdfIn PDF document text
    • https://dla-pracownika.pl/pliki_user/File/wowot.pdfIn PDF document text
    • http://trungtinjsc.vn/upload/FCK/file/65509877671.pdfIn PDF document text
    • http://ohmytour.kr/FileData/ckfinder/files/20210904_38C62DA35069D6A8.pdfIn PDF document text
    • http://sirinthepgroup.com/userfiles/file/67689317448.pdfIn PDF document text
    • https://9ja-bet.com/userfiles/file/5687986279.pdfIn PDF document text
    • https://samsungdvmklima.com/upload/ckfinder/files/telimerewarevol.pdfIn PDF document text
    • http://toyotarent.tw/FileData/ckfinder/files/20210902_9748547FC8D8D74B.pdfIn PDF document text
    • http://dxline.eu/userfiles/file/mafosuraxado.pdfIn PDF document text
    • http://ourgans.org/userfiles/files/53730202505.pdfIn PDF document text
    • http://nd-58.ru/wp-content/plugins/super-forms/uploads/php/files/1ffe46e2f5c7e859e4c1337a037a7e39/zomipudak.pdfIn PDF document text
    • https://denizlihorozu.com/resimler/files/97625001485.pdfIn PDF document text
    • http://www.musicmaestrodiscos.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1613d1cb8e5891---bamoxidusodebejatabekubab.pdfIn PDF document text
    • https://crc.creativechange.net/ckfinder/userfiles/files/lonit.pdfIn PDF document text
    • https://mar3ol.com/Files/files/bejojuvumegewuzaxoburoto.pdfIn PDF document text
    • http://www.reroofingbrisbaneqld.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1613d2cd4b3ae5---fatarofelevuparijitirifaw.pdfIn PDF document text
    • https://wecareu.net/ckfinder/userfiles/files/959664708.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/DOqCt-cVA4I/uplcv?utm_term=android+voice+commands+not+workingPDF 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_off0000d617.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD617 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ee2e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE2E 10892 bytes
SHA-256: 3a4b0cf4826f6c259179463a66601a2de78c02e36bdd262ded0c7caeafc2334b
font_02_sfnt_off0001074b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1074B 17664 bytes
SHA-256: 4f5c23ff4f72612a41c711dcdb46a406f22deabc6a9cb41a0dc8350853a7938c