Malicious PDF — malware analysis report

Static analysis result for SHA-256 81b63d360cae80b1…

MALICIOUS

PDF

95.3 KB Created: 2021-08-06 18:01:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: a7bfad3cc7b1ed6c5b32781c92aea482 SHA-1: d7e523f378f9616e26ac2a9e405cce5f6b5d948a SHA-256: 81b63d360cae80b1b037e98b51c3278992dd1d2d1cd97c183d6cbcbb9b57d0dc
156 Risk Score

Malware Insights

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

The PDF file contains a large number of external links, many of which point to compromised WordPress upload directories or disposable domains. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The document body is unreadable due to encoding issues, but the link farm behavior is evident from heuristics.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

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://irlanc.ru/uplcv?utm_term=how+to+set+time+on+relion+wrist+blood+pressure+monitor PDF link annotation
    • https://marljivo.hr/userfiles/file/83767073353.pdfIn PDF document text
    • http://www.cascinasorigherio.it/wp-content/plugins/formcraft/file-upload/server/content/files/1608e93812f2c5---59675869695.pdfIn PDF document text
    • http://archinfo.ru/uploads/file/ziguzerumonufobun.pdfIn PDF document text
    • http://biosite.ru/images/news/file/37851918438.pdfIn PDF document text
    • http://zerosquareonline.com/file/zukevupitamajo.pdfIn PDF document text
    • http://www.maoles.com/wp-content/plugins/formcraft/file-upload/server/content/files/16084ca36e74b3---32105281786.pdfIn PDF document text
    • http://xn--b3ct0dc9bc4a4g.com/userfiles/files/73711649068.pdfIn PDF document text
    • https://www.davidcosz.de/wp-content/plugins/super-forms/uploads/php/files/v6jkrl3rpjutmmi1es7coprmpt/lenudituvixoweko.pdfIn PDF document text
    • http://speaklifeiamgreatness.com/files/files/lenovedosotanuripa.pdfIn PDF document text
    • https://lorenzonimmigrationlaw.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607033f89eb4e---47480193429.pdfIn PDF document text
    • http://mega-stainlesssteel.com/uploads/image/files/fatudi.pdfIn PDF document text
    • https://parklanehotel.asia/userfiles/file/6211176192.pdfIn PDF document text
    • https://www.ogblfrontaliers.fr/wp-content/plugins/super-forms/uploads/php/files/n2b3ioqh76m7hjagg1o3opl9cm/zufazidutenora.pdfIn PDF document text
    • http://greatwalledmond.com/ckfinder/userfiles/files/26196568968.pdfIn PDF document text
    • http://www.marcelasemper.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e06da5d2b9c---kovevekub.pdfIn PDF document text
    • https://eandjfamilyhealthcenter.com/wp-content/plugins/super-forms/uploads/php/files/5e192e9050cc59b5ae5157750ad05e9f/fezuwerolivowipotonixat.pdfIn PDF document text
    • http://www.restorationservice.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1609b3d1555a77---12289329564.pdfIn PDF document text
    • http://vervesimuhub.com/userfiles/file/59030868084.pdfIn PDF document text
    • http://www.recetasyconsejos.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a2461b7ac6a---soponepeluvabola.pdfIn PDF document text
    • https://dipinkrishna.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b06ea954375---97543545280.pdfIn PDF document text
    • https://fermuar.com/wp-content/plugins/formcraft/file-upload/server/content/files/160f24c807b793---94442294374.pdfIn PDF document text
    • http://antwerp-rentals.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607c91f844f50---26659916467.pdfIn PDF document text
    • http://gyndoktors.de/ckfinder/userfiles/files/xukuzebibewerajurigaza.pdfIn PDF document text
    • http://kraljicabih.com/wp-content/plugins/formcraft/file-upload/server/content/files/160aa25dcb82aa---79835606365.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_off0001115e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1115E 10708 bytes
SHA-256: 86ac45090a02341cbc9e88aa3f1e644dc7d4cd326e69b726a5cb658a36fa18da
font_01_sfnt_off000129aa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x129AA 17296 bytes
SHA-256: 82ebb31c0d641686ee8b2bb06996dfc5ef679c51f373a50d84f6259784039d16
font_02_sfnt_off000156fc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x156FC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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