Malicious PDF — malware analysis report

Static analysis result for SHA-256 771833d646ca7f56…

MALICIOUS

PDF

73.0 KB Created: 2021-09-16 15:47:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 94e81f896971e1cfbefbda0a9d0ed310 SHA-1: 3e488f267dfface2500fec132a360b52e6f3939e SHA-256: 771833d646ca7f56b2c9f4c2aa3ab4c9509704f6abefd24069b98394ceb52c33
126 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The heuristics indicate the PDF acts as a link farm, directing users to numerous other PDF files hosted on potentially disposable domains. This suggests a phishing or SEO poisoning campaign designed to distribute further malicious content or exploit.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

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 http://shuimotongyuan.com/userfiles/file/26849432961.pdf
    • http://iuf.kr/pds_down/files/nevilovitududupiwo.pdf
    • http://bbfederico2.net/userfiles/file/5842413557.pdf
    • https://cristiandellavedova.com/wp-content/plugins/super-forms/uploads/php/files/4785c2b0df831d9d4d2fb49118732e74/puzamalenosegurobeko.pdf
    • http://atek-ent.com/upload/file/jeresuwefokuvof.pdf
    • http://tumakuruvoice.com/tumkurvoice/ckeditor/ckfinder/userfiles/files/tomiramudeduzudamimapejed.pdf
    • http://atrsara.ir/resource/files/39040660428.pdf
    • https://ddnepal.com/assets/userfiles/files/joxiv.pdf
    • http://les-dvorik.ru/userfiles/file/kugolulijenoxanopujafisuf.pdf
    • https://www.lang-mayer.de/wp-content/plugins/formcraft/file-upload/server/content/files/1613ef9bd48789---wusowapewibanefiz.pdf
    • https://aukshanya.promosing.com/alpha/ckfinder/userfiles/files/duguzike.pdf
    • http://owop.challengersports.com/ckfinder/userfiles/files/budopilevamaxupotabole.pdf
    • https://ymy-tea.tw/upload/files/54523722777.pdf
    • https://coopinproject.eu/ckfinder/userfiles/files/fejevimipufanotov.pdf
    • https://limpiezasinasel.com/userfiles/files/dusakodavepu.pdf
    • http://intertribo.sk/files/gobexezofusididemuwexor.pdf
    • http://ototavandosemesi.com/resimler/file/jikamanofoz.pdf
    • https://tainandentist.com/uploads/files/202109050051159840.pdf
    • https://scalping.ir/data/files/file/wanogememug.pdf
    • http://www.insight-assessment.com/ckfinder/userfiles/files/15393520680.pdf
    • http://files.ibiza-ferien.de/file/zetosatowatesetopiji.pdf
    • http://namthangbasaltstone.com/uploads/image/files/tunizijofulijanijafi.pdf
    • https://stpm-sa.com/userfiles/file/fatajetutugav.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3vuEKuznOb8/uplcv?utm_term=street+fighter+online+unblocked
    • 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_off0000bbcf.bin
2c4c7a4d2eebbf51c79837ca33033290d56892528342f39fe7a7b7c200c0e5fd		 pdf-font-stream PDF embedded font (sfnt) at offset 0xBBCF 16520 bytes
font_01_sfnt_off0000e61a.bin
1e59b5a9e9cf413a8f4586da8c9e9073bc3bd645630a936da422334e397bf30f		 pdf-font-stream PDF embedded font (sfnt) at offset 0xE61A 10832 bytes
font_02_sfnt_off0000fec5.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0xFEC5 16792 bytes

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