Malicious PDF — malware analysis report

Static analysis result for SHA-256 81bcd02751f08e1e…

MALICIOUS

PDF

71.1 KB Created: 2021-10-01 21:05:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: fe249e2a36ba21fba3b02cd4c0a4b581 SHA-1: b9be528b3e0ff9d403800260ed7f393fd1919b2b SHA-256: 81bcd02751f08e1e1989b62852a051659ff7535944a8ae5046e3782877f7afa6
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. It contains numerous URLs, many of which are hosted on disposable domains or compromised CMS uploads, indicating a link farm designed to redirect users. The presence of external URI heuristics and the 'PDF_SEO_DISPOSABLE_LINK_FARM' firing suggest the primary purpose is to direct users to potentially harmful external sites, likely for phishing or malware distribution.

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://inwebjor.ru/uplcv?utm_term=telecharger+une+video+youtube+android
    • http://murasakijr.com/uploads/files/16104669540.pdf
    • http://totoumi.jp/upload/file/45248100066.pdf
    • http://rutka.pl/media/upload/files/f291c7f363890dad4d2e6f236470c6b4.pdf
    • https://anandalaya.in/resources/file/tikokizanuwovepaven.pdf
    • https://bbu.vn/Images_upload/files/30747225032.pdf
    • https://kabelkyaobuv.sk/editor_uploads/files/biforuzitetinog.pdf
    • https://costumeworld.com/wp-content/plugins/formcraft/file-upload/server/content/files/16130a51a1e175---94717222876.pdf
    • https://turismo-galicia.es/ckfinder/userfiles/files/lileb.pdf
    • http://automsystem.com/UploadFile/file/20210917021235617.pdf
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/16145d24cb908f---zimemorubepuledijo.pdf
    • http://cokhixnktientien.com/Images_upload/files/55257385350.pdf
    • https://vidaleve.net/ckfinder/userfiles/files/lifilizupuga.pdf
    • http://schubert-hh.de/image/file/80948676156.pdf
    • https://rieker-consulting.eu/files/file/vureki.pdf
    • http://ktai.lmg.jp/upload/file/musupuligekijefaga.pdf
    • http://bergepkolcsonzo.hu/userfiles/file/wakusu.pdf
    • https://bhandarisurgical.com/ckfinder/userfiles/files/37247273506.pdf
    • http://amicalelaique-guyancourt.fr/ckfinder/userfiles/files/43172912305.pdf
    • http://uklearningnetwork.com/userfiles/file/xataxomarumupiwagolemiwu.pdf
    • https://dampinggame.com/calisma2/files/uploads/21432920157.pdf
    • https://kaemsp.org/upload/editor/file/zipisurowe.pdf
    • http://rayanchem.com/d/files/naxanujegidususonojazi.pdf
    • http://veterinariogiardinelli.it/userfiles/files/besami.pdf
    • https://jaunimodienos.lt/wp-content/plugins/super-forms/uploads/php/files/31t4ttsfo0sgttapsd6b9be2eg/kalunorigimuvaravexudew.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000b365.bin
956766106c3667f61a86268256b7c6e054cb9f3d6ded2abcf556218437c380c1		 pdf-font-stream PDF embedded font (sfnt) at offset 0xB365 16872 bytes
font_01_sfnt_off0000ddbe.bin
64e6f8e7c4c1c3780c757088afb3c41db034da0de7a80d6833285112cb2632bd		 pdf-font-stream PDF embedded font (sfnt) at offset 0xDDBE 10864 bytes
font_02_sfnt_off0000f6a1.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF6A1 16792 bytes

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