Malicious PDF — malware analysis report

Static analysis result for SHA-256 55d81acec2d1a3f9…

MALICIOUS

PDF

69.7 KB Created: 2021-10-01 11:46:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 7b64cb266fa96375209897c1469c695f SHA-1: 9a96e97bd0042486db62ed9384e15b80f7a1bb95 SHA-256: 55d81acec2d1a3f9167ffeaaf3b8bc4ccbf69caace660abddfd1760c66683fc3
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is identified as a malicious PDF by ClamAV and an ML classifier. It contains numerous external URIs, many pointing to disposable hosting, suggesting a link farm designed to redirect users. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a deliberate attempt to create a non-clustered link farm. While no scripts were explicitly extracted, the presence of embedded URIs and the overall structure strongly suggest a phishing or redirection attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://drafthe.ru/uplcv?utm_term=goodness+of+fit+test+assumptions PDF link annotation
    • https://alwillislifecenter.org/ckfinder/userfiles/files/36998456253.pdfIn PDF document text
    • https://legyenegyjonapod.hu/userfiles/files/fusexo.pdfIn PDF document text
    • http://scea.edu.mn/ckfinder/userfiles/files/57937960772.pdfIn PDF document text
    • https://peintures-descours.fr/fichier/files/lezapumovebuvilomi.pdfIn PDF document text
    • http://massageindex.nl/images/uploads/lesokemu.pdfIn PDF document text
    • http://sipsak.nl/userfiles/file/nisibedepaw.pdfIn PDF document text
    • http://n-production.com/upload/fckeditor/file/budot.pdfIn PDF document text
    • http://aylabawadi.ae/userfiles/file/29995001871.pdfIn PDF document text
    • http://rszm88.com/upfolder/e/files/20210901212532.pdfIn PDF document text
    • http://jsqnchem.com/upload/files/81404419962.pdfIn PDF document text
    • http://machinesupplier.cn/data/product/file/2021101_93424_824.pdfIn PDF document text
    • http://d2dgroup.net/upload/files/vetexuwawusaxumageno.pdfIn PDF document text
    • http://queenart.kr/userData/board/file/27335666149.pdfIn PDF document text
    • https://oreopay57.com/ckfinder/userfiles/files/88031119677.pdfIn PDF document text
    • https://gz-topstar.com/wp-content/plugins/super-forms/uploads/php/files/85de7aba75c36a8dd4f67c808b9bf9b6/73653039734.pdfIn PDF document text
    • http://kystop.com/wp-content/plugins/super-forms/uploads/php/files/4f7e0a329537a18ae5ca6ebb0382d8b8/40434635087.pdfIn PDF document text
    • http://abnigakgdsg.friendship-match.com/upload/files/57822415808.pdfIn PDF document text
    • http://neza.cz/UserFiles/File/86373474816.pdfIn PDF document text
    • https://anakaygame.net/calisma2/files/uploads/jidujeje.pdfIn PDF document text
    • http://gongotour.com/FileData/ckfinder/files/20210923_E968BCE6235F4232.pdfIn PDF document text
    • http://pzhjintai.com/upload/files/33580743008.pdfIn PDF document text
    • http://rheinmotel.com/userfiles/file/48815845175.pdfIn PDF document text
    • http://studiotravenzolo.it/userfiles/files/vepivowefamezukarowosor.pdfIn PDF document text
    • http://polaryachts.com/res/wysiwyg/file/kizobezevomegakozilud.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_off0000b297.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB297 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000caa9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCAA9 15052 bytes
SHA-256: ec6b8711c0edd0892e82409ba2e4e1ada53b802cdfbfad253687ad9b4ac59464
font_02_sfnt_off0000f0b2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF0B2 10652 bytes
SHA-256: bc35dcd213bcbb8fdb949760fb2699c8f096e18b6f8610b4e4edf8466baf67ab