Malicious PDF — malware analysis report

Static analysis result for SHA-256 c5865433f391cef2…

MALICIOUS

PDF

81.5 KB Created: 2021-09-19 12:22:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 1ebd16fffda4960e6e0e46843b32108d SHA-1: 8cf2c0fc0b1c0cb9cc59dd475489aad3e5466a89 SHA-256: c5865433f391cef2c6154fe2c10c4b2c11550caec751d1fd082963f925b07715
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous external links, many of which are hosted on disposable domains and appear to be part of a link farm, as indicated by the PDF_SEO_DISPOSABLE_LINK_FARM heuristic. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or distributing further malware. Although no scripts were explicitly extracted, the PDF structure and numerous URLs point towards a malicious document designed to redirect users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://smidgel.ru/uplcv?utm_term=children%27s+reading+books+pdf+download PDF link annotation
    • http://inphilong.com/upload/files/pewozugenup.pdfIn PDF document text
    • http://centrons.com/uploaded/file/1369106004613cb812a4a87.pdfIn PDF document text
    • http://www.tiande-global.com/ckfinder/userfiles/files/zerivovedoxametibisavu.pdfIn PDF document text
    • https://www.hdcorp.com.br/wp-content/plugins/super-forms/uploads/php/files/v1o6tbgiauf8c4ekj9otr2fb4u/xaxax.pdfIn PDF document text
    • http://www.tractortools.cz/ckfinder/userfiles/files/78737578807.pdfIn PDF document text
    • https://minhkygroup.com/luutru/files/ratavotazasofulukakozu.pdfIn PDF document text
    • https://mystruggle.uk/indigo/ckfinder/userfiles/files/fukifuxenevusivefugizave.pdfIn PDF document text
    • http://ggbris.com/slbdavbatala/userfiles/file/47542868489.pdfIn PDF document text
    • http://hatowo.com/app/webroot/uploads/files/42526511502.pdfIn PDF document text
    • http://www.vljainandco.com/userfiles/files/gitida.pdfIn PDF document text
    • https://rubin2000-distribuitorshop.ro/userfiles/file/43051658173.pdfIn PDF document text
    • http://tid.vn/upload/files/gepuworubosugan.pdfIn PDF document text
    • http://studiomontironi.eu/userfiles/files/katevufuguf.pdfIn PDF document text
    • https://www.db-ynox.fr/ckfinder/userfiles/files/vowagawi.pdfIn PDF document text
    • https://shinko-tw.com/UserFiles/file/bidojufipimozofepurilo.pdfIn PDF document text
    • http://reversetheclocknow.com/ckfinder/userfiles/files/wesovaxibatapefipanawubuk.pdfIn PDF document text
    • http://monticellotownship.org/userfiles/file/dawukajoduwovukalupatad.pdfIn PDF document text
    • http://4chan.ro/UserFiles/file/zuposutenudurixujadeji.pdfIn PDF document text
    • http://likebarcode.com/image/files/20210916_153027.pdfIn PDF document text
    • http://naoshima-tours.com/images/blog/file/63549154030.pdfIn PDF document text
    • https://gizaviation.com/uploads/files/36204278263.pdfIn PDF document text
    • http://perfecturology.cafe24.com/upload/editor/imagefile/vabodotobene.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_off0000d913.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD913 17512 bytes
SHA-256: 814d916585abf3a958e6dee00e46e489b35d0aa2b6ab7c310f7027f03203eefc
font_01_sfnt_off00010686.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10686 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011e9d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E9D 11064 bytes
SHA-256: a10e3b9062b77d22037fb3b6515a4a862eefe481a47adfa2a6d84a8e7b5c161a

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