Malicious PDF — malware analysis report

Static analysis result for SHA-256 c4ef8b19ce616c1d…

MALICIOUS

PDF

70.3 KB Created: 2021-09-26 11:58:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 7353dbf890a863f3a1e9e5077bc5da04 SHA-1: 23c289c891f558ce8ac795c0b0ddfb2af20cd34d SHA-256: c4ef8b19ce616c1da53b734fb228858834e8d32f8000c58a2f2df65d346f569f
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs that point to external websites, many of which appear to be compromised or disposable hosting. Heuristics indicate this is a link farm designed to direct users to potentially malicious content. The ML classifier and ClamAV detection strongly suggest malicious intent, likely 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://synerhu.ru/uplcv?utm_term=weird+words+starting+with+m PDF link annotation
    • https://minhvuongthuphap.com/upload/ck/files/mobobifezurukenoso.pdfIn PDF document text
    • https://escritacontabilidade.net/fotos/news/file/wedobopasezobu.pdfIn PDF document text
    • http://kadet-ck.cz/pic/file/janijalefikage.pdfIn PDF document text
    • https://buzascsaba.hu/userFiles/file/diwidogu.pdfIn PDF document text
    • https://jucariicopilasi.ro/app/webroot/files/userfiles/files/88530920878.pdfIn PDF document text
    • http://dr-onesrl.com/userfiles/files/gewaruzitejilop.pdfIn PDF document text
    • http://www.movingintofreedom.com/wp-content/plugins/formcraft/file-upload/server/content/files/16140d30bcfcc6---wamugoxo.pdfIn PDF document text
    • http://fruhmann-elektrotechnik.at/vitovofomebawuvomopagaf.pdfIn PDF document text
    • http://metrominicabs.com/survey/userfiles/files/82276340273.pdfIn PDF document text
    • http://goldmustang.com/files/files/tapuzunimi.pdfIn PDF document text
    • https://km2804.com/ckupload/files/11127181220.pdfIn PDF document text
    • http://jarosi.hu/files/file/jumonulerasage.pdfIn PDF document text
    • https://jdbailbonds.com/wp-content/plugins/super-forms/uploads/php/files/341475fb2bb6c589e3d506a347eff856/bolavuj.pdfIn PDF document text
    • http://zamokugrofa.sk/admin/fckeditor/file/gekabufexijaroguraji.pdfIn PDF document text
    • http://monterroso-construpuntos.com/campannas/file/vopukokodenixu.pdfIn PDF document text
    • https://muzeumkonstancina.pl/attachments/file/tipodurajilipaxuj.pdfIn PDF document text
    • http://kimwendelldesign.com/ckfinder/userfiles/files/zokodadevawiduxigepiw.pdfIn PDF document text
    • https://www.booster-p.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614156f100a43---juzezobaxodezitamo.pdfIn PDF document text
    • http://cyuanmei.com/userfiles/file/84467357523.pdfIn PDF document text
    • http://gtlitalia.com/userfiles/files/rokilo.pdfIn PDF document text
    • https://hetodon.com/fckeditorfiles/file/pezajukijet.pdfIn PDF document text
    • http://www.hzkontejnery.cz/ckfinder/userfiles/files/daveleretewuxagakidibajur.pdfIn PDF document text
    • http://cdenito.net/userfiles/file/sowukolaguwelenak.pdfIn PDF document text
    • http://foto-klub.dk/userfiles/file/novoxuzamufejozo.pdfIn PDF document text
    • http://audiomaster.se/wp-content/plugins/formcraft/file-upload/server/content/files/161443f7cd267d---rafutawenakusofugisa.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_off0000b45b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB45B 10728 bytes
SHA-256: 68d31fdc6256d453a8aaed7270e66b3dcae0c91ed213e22f459e970218757524
font_01_sfnt_off0000cca7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCCA7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000e4b9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE4B9 15348 bytes
SHA-256: 04d4811b4207dad20ce03724090638ca6a24c35c6e6198565a5e78ac6f96ade3

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