Malicious PDF — malware analysis report

Static analysis result for SHA-256 c526ed1438b84b6f…

MALICIOUS

PDF

82.8 KB Created: 2021-09-15 23:19:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 4157bbf0ed6a7ae88f4bfb6bd8dad39f SHA-1: 771f5b21558ad56df19a1f1c0dd05b9e98e92366 SHA-256: c526ed1438b84b6f7f27d00139e8ab28796e073b4f4191d1c57bb77a317b4678
156 Risk Score

Malware Insights

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

This PDF file was flagged by multiple heuristics and a machine learning classifier as malicious, specifically identified as a phishing or trojan distribution vehicle. It functions as a link farm, directing users to numerous external URLs, many of which are hosted on compromised WordPress sites or disposable domains, increasing the likelihood of users being led to malicious content. The presence of multiple PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM firings strongly suggests a deliberate attempt to obscure the true destination and leverage potentially untrustworthy hosting.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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://medvor.ru/uplcv?utm_term=best+app+to+read+and+download+manga PDF link annotation
    • https://podgoricki-klub.me/userfiles/file/ligimopatini.pdfIn PDF document text
    • https://hunghiephuylog.com/upload/files/xuxarigolupamafafugej.pdfIn PDF document text
    • http://mcutech.net/upload/2021/09/file/16311578341364312997.pdfIn PDF document text
    • http://allier-genealogie.org/File:/jamuzevokubupefamasi.pdfIn PDF document text
    • http://cathugo-catamarans.de/res/wysiwyg/file/55279497240.pdfIn PDF document text
    • http://avision-italia.com/userfiles/files/85602735434.pdfIn PDF document text
    • https://xn--1--8kcai1ck2bs.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/10188f21a5a2adfc0252b58c8dee383b/40708689959.pdfIn PDF document text
    • http://yishiweb.com/upfiles/files/20210912_170909.pdfIn PDF document text
    • http://www.hj-bouwt.be/wp-content/plugins/formcraft/file-upload/server/content/files/1613f4054224f3---23508551357.pdfIn PDF document text
    • https://renewone.de/files/kokipanuvupirij.pdfIn PDF document text
    • http://yushendesign.com/images_fck/file/1630602786.pdfIn PDF document text
    • http://globalone-mould.com/gbw/fckfiles/20210907042150.pdfIn PDF document text
    • http://kriosispl.com/cote_dor_import/admin/ckfinder/userfiles/files/20704986796.pdfIn PDF document text
    • https://autosaloncenter.com/uploads/files/45002222275.pdfIn PDF document text
    • http://cana.vn/uploads/userfiles/file/ziguxezatizerid.pdfIn PDF document text
    • https://angkortaxiservice.com/userfiles/file/91240069239.pdfIn PDF document text
    • http://rockhousemethod.com/ckfinder/userfiles/files/lovoxebilavedepog.pdfIn PDF document text
    • http://veronicanealhome.com/wp-content/plugins/formcraft/file-upload/server/content/files/2/16135bc3890946---dikowawafufodemuzi.pdfIn PDF document text
    • http://www.tlo.ntou.edu.tw/ckfinder/userfiles/files/79222269794.pdfIn PDF document text
    • http://dynamicyunnan.com/ckfinder/userfiles/files/suselufuvubegugo.pdfIn PDF document text
    • http://jeykrishnaclub.com/images/file/33317015574.pdfIn PDF document text
    • http://guojingmall.com/userfiles/file///36357255520.pdfIn PDF document text
    • http://cartonwrappingmachine.com/userfiles/file/xatepuxuvuzagef.pdfIn PDF document text
    • http://c2ctrading.org/cms_upload/files/filabapenapopivipapuvewuv.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_off0000dff0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDFF0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f802.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF802 17432 bytes
SHA-256: 79dffba62648ea18b280bf34c94bb9a807d789b3681623feaf1048e38f68cf04
font_02_sfnt_off000124f3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x124F3 10784 bytes
SHA-256: 2b1652e88d46d60f87f55946121178607dfe2ed36b188774ae70fa18a4b7a19e

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