Malicious PDF — malware analysis report

Static analysis result for SHA-256 4277b3e90a597a59…

MALICIOUS

PDF

72.3 KB Created: 2021-09-02 14:55:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: be45a2d357a27a1475f03ea1de24c5b2 SHA-1: 41cb13f81330603521948197cc1162884e4067eb SHA-256: 4277b3e90a597a59f6a43187eeb16df5b7ecb047f174d837f5114a51ac303e25
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a phishing or trojan threat. It contains numerous external links, many pointing to compromised CMS upload storage or disposable hosting, suggesting a link farm designed to redirect users to malicious content. The presence of embedded URLs and the nature of the heuristics strongly suggest this document is part of a phishing campaign, likely using spearphishing attachments as the initial access vector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9982

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://inwebjor.ru/uplcv?utm_term=inverse+derivative+formula+pdf PDF link annotation
    • https://webvitamin.vn/app/webroot/uploads/files/kexozariginirekufonumuri.pdfIn PDF document text
    • https://adepotcustom.com/UploadFiles/file/20210429235756122.pdfIn PDF document text
    • https://finestblogger.de/wp-content/plugins/super-forms/uploads/php/files/jurhoa0iqv3a6p5fca41m0lq7m/vimados.pdfIn PDF document text
    • http://henanshuangxin.com/d/files/lovonob.pdfIn PDF document text
    • http://scvumaichiramen.com/uploads/files/jetadij.pdfIn PDF document text
    • http://qboardapp.com/wp-content/plugins/super-forms/uploads/php/files/6c7d6740a6dda03291dc68324bdb434e/rudedon.pdfIn PDF document text
    • https://stakeoutllc.com/wp-content/plugins/super-forms/uploads/php/files/e01b42269ad3d91759e6c406db3423df/20338946249.pdfIn PDF document text
    • https://diedacorporation.net/freesiafiles/file/wunud.pdfIn PDF document text
    • http://investinwielkopolska.pl/application/lib/ckfinder/userfiles/files/59891199407.pdfIn PDF document text
    • https://wentworthre.com/wp-content/plugins/super-forms/uploads/php/files/294875e5f83b8aa2a3b581f304e80a8c/jisapipikupujikoxetuk.pdfIn PDF document text
    • http://murito.fr/ckfinder/userfiles/files/xojunimizizenoliwit.pdfIn PDF document text
    • http://ptk-astana.kz/wp-content/plugins/super-forms/uploads/php/files/c513330ad30ad11abc7dfaaa00a3ef64/29905220426.pdfIn PDF document text
    • https://stcatherine.ac.ug/wp-content/plugins/formcraft/file-upload/server/content/files/160ab7c6db1921---36455908685.pdfIn PDF document text
    • http://innova-perila.ru/upload/files/36412029698.pdfIn PDF document text
    • http://www.sunarsurdurulebilir.com/wp-content/plugins/super-forms/uploads/php/files/1gf0aqiblhpu53mece3g7141e1/xagerepigitefowaru.pdfIn PDF document text
    • https://humantouchtranslations.com/wp-content/plugins/formcraft/file-upload/server/content/files/1/1607c4786d3476---24574408374.pdfIn PDF document text
    • http://elmbbq.com/uploads/files/gazugomo.pdfIn PDF document text
    • https://mindweave.co.uk/wp-content/plugins/super-forms/uploads/php/files/u2pkt29o3qtl4k0jdtrpunukan/79659995308.pdfIn PDF document text
    • http://maidnheaven.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608d69b61eba3---78276434151.pdfIn PDF document text
    • http://ajivikafinance.com/userfiles/file/paxupobanumugutolugozoluv.pdfIn PDF document text
    • https://torgradio.ru/new/files/file/74094106320.pdfIn PDF document text
    • https://ambientltg.com/wp-content/plugins/super-forms/uploads/php/files/215262444869429b5632d5141cca69d5/wozumotitukasilurelurip.pdfIn PDF document text
    • http://jamoncup.es/wp-content/plugins/formcraft/file-upload/server/content/files/160929e792cb19---81869761068.pdfIn PDF document text
    • https://discovercefalu.it/_data/images/file/garojepidukasete.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_off0000ba26.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBA26 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d23d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD23D 10776 bytes
SHA-256: 0572ac52bfc5f0e74baba6cc0fc087577d5d4e3f83eb78c75363c8b0ccebf706
font_02_sfnt_off0000eb0c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB0C 15784 bytes
SHA-256: 620822dd51e54517290e0901a819d54d9656ccb89d40ab6bda8f6c8915d22ae8