Malicious PDF — malware analysis report

Static analysis result for SHA-256 f4257de3ce9372f3…

MALICIOUS

PDF

69.0 KB Created: 2021-09-27 17:47:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-20
MD5: ff6babd1836c43f51c1fa5f4bf3dd185 SHA-1: 4df354921696228a2a072bd0ec083672a68f2666 SHA-256: f4257de3ce9372f315558caad427c1f9be6e378a3053f6bdbbf00cb537d7ef70
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as malicious by ClamAV and an ML classifier, with multiple heuristics indicating it functions as a link farm pointing to compromised WordPress sites and disposable hosting. The embedded URLs, such as 'https://medvor.ru/uplcv?utm_term=hotspot+my+phone', are likely used to redirect users to phishing or malware-hosting sites. Although no scripts were explicitly extracted, the PDF structure and URL patterns strongly suggest an intent to deliver malicious content or facilitate phishing attacks.

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://medvor.ru/uplcv?utm_term=hotspot+my+phone PDF link annotation
    • http://socialbomjesus.org.br/wp-content/plugins/formcraft/file-upload/server/content/files/1614bfa45a8b24---fagusokelefebanagob.pdfIn PDF document text
    • https://dakhoathienhoa.net/images/files/80446479926.pdfIn PDF document text
    • http://gpkoaee.ru/ckfinder/userfiles/files/10801928285.pdfIn PDF document text
    • http://farmaciafasolis.eu/userfiles/files/77302928769.pdfIn PDF document text
    • http://goldmustang.com/files/files/72988868569.pdfIn PDF document text
    • http://yamamatoen-wanwan.jp/ckfinder/userfiles/files/gokameroveraxeted.pdfIn PDF document text
    • http://mfcpavpos.ru/file/26735734031.pdfIn PDF document text
    • https://cosmopolitanhotel.eu/uploads/wysiwyg/files/jibanakesu.pdfIn PDF document text
    • http://bigdoughpizza.com/uploads/files/tavapo.pdfIn PDF document text
    • https://evocative.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1614df5204e9b3---83330745827.pdfIn PDF document text
    • http://thibidi.vinadesign.info/uploads/images/files/39532663498.pdfIn PDF document text
    • http://ourpreferred.com/userfiles/files/xuleborurivozugomamit.pdfIn PDF document text
    • http://guowangcable.com/d/files/69313598487.pdfIn PDF document text
    • http://3handseg.com/wp-content/plugins/formcraft/file-upload/server/content/files/16142d4d16ffc0---52859168360.pdfIn PDF document text
    • http://ctkupavna.ru/upload/file/30194031739.pdfIn PDF document text
    • http://shangrilatheshow.com/ckfinder/userfiles/files/27365988586.pdfIn PDF document text
    • http://stolizstekla.ru/userfiles/file/lodopuzakewojap.pdfIn PDF document text
    • http://timeyear-v.com/userfiles/file/foluwofir.pdfIn PDF document text
    • http://proart.by/media/file/zarugigat.pdfIn PDF document text
    • http://www.hausman.eu/images/wyswig_images/file/21330019563.pdfIn PDF document text
    • http://kfnmdg.com/upfolder/e/files/20210927190433.pdfIn PDF document text
    • http://ivankrivanek.com/userfiles/file/76913512019.pdfIn PDF document text
    • http://nerezove-kuchyne.cz/UserFiles/File/886285800.pdfIn PDF document text
    • http://ssteelelaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/51629019309.pdfIn PDF document text
    • http://cuoredicane.it/userfiles/files/11223283579.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_off0000b1f2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB1F2 10224 bytes
SHA-256: 0008a04a2b1fa2099639291058808c9a6057e2317a39a1a893399f4e01ffc8b4
font_01_sfnt_off0000c8bb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC8BB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000e0cd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE0CD 14976 bytes
SHA-256: a6e3600c305ef5c26a98f2f634251c222d2374a666e7220da63cab02fdfd6404

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