Malicious PDF — malware analysis report

Static analysis result for SHA-256 c27555d81a39480d…

MALICIOUS

PDF

69.2 KB Created: 2021-09-24 16:30:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: af9379d6fd4a6dc5818a180d0b76533f SHA-1: 0cf0f553ba3d5de5a80b122cc837d52d16cefa27 SHA-256: c27555d81a39480d9469e64bc19c5b76c10d09e6fa79cea067a95de634294c82
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, and exhibits characteristics of a link farm on potentially compromised WordPress sites. The embedded URLs, such as https://nomylo.ru/uplcv?utm_term=pin+lock+unlock, suggest a phishing or malware distribution attempt. Although no scripts were explicitly extracted, the PDF structure and heuristic firings indicate malicious intent, likely related to directing users to external malicious content.

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://nomylo.ru/uplcv?utm_term=pin+lock+unlock PDF link annotation
    • https://klingende-zeder.de/wp-content/plugins/formcraft/file-upload/server/content/files/161441878b4de8---jorexewutebetizidirisik.pdfIn PDF document text
    • http://hkalc.com/userfiles/23589446690.pdfIn PDF document text
    • http://tpokebar.com/uploads/files/76376250470.pdfIn PDF document text
    • https://hattshopping.com/admin/assets/images/ckfiles/duronelojakewirogolovoti.pdfIn PDF document text
    • https://dermo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612eef47a3c2b---xidovisatuminunol.pdfIn PDF document text
    • http://theheavent.com/userfiles/files/62756081037.pdfIn PDF document text
    • https://masterjobintl.com/ckfinder/userfiles/files/kuledowidologo.pdfIn PDF document text
    • https://www.afoa.org.ar/backend/ckfinder/userfiles/files/fixuzifakumilebo.pdfIn PDF document text
    • https://movimientofamiliadejesus.com/images/uploaded/file/lixexagiforem.pdfIn PDF document text
    • https://art-lamps-rali.eu/files/file/sizazuwasaturavukive.pdfIn PDF document text
    • https://kingdomdatesuae.com/userfiles/files/fojararurusiniz.pdfIn PDF document text
    • http://cdkuysuujk.handysociality.com/upload/files/43089303070.pdfIn PDF document text
    • https://www.jdconstinc.com/ckfinder/userfiles/files/palaripazakitexegux.pdfIn PDF document text
    • http://www.enfersalus.com/ckfinder/userfiles/files/xamusunaniv.pdfIn PDF document text
    • https://snapstudios.ca/userfiles/file/98493591978.pdfIn PDF document text
    • http://www.mostex.sk/files/articles/file/nemedamegab.pdfIn PDF document text
    • http://quesnelfoundation.ca/userfiles/file/sodasiwikivegosizubi.pdfIn PDF document text
    • http://acevina.com/webroot/img/files/funijipab.pdfIn PDF document text
    • http://culfordequestriancentre.org/UserFiles/file/mukoletepabalolunakesik.pdfIn PDF document text
    • https://regalcabs.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16135d62b29356---rubegisakavimosomezoto.pdfIn PDF document text
    • https://ana-jsc.com/upload/files/gaxevominevoxego.pdfIn PDF document text
    • https://www.restaurant-latableedevercel.com/ckfinder/userfiles/files/jawapakesexalikatono.pdfIn PDF document text
    • http://yevres.fr/ckfinder/userfiles/files/1318442571.pdfIn PDF document text
    • https://www.thc.gda.pl/ckfinder/userfiles/files/fujofasegukelif.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_off0000b37c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB37C 9756 bytes
SHA-256: f94327b040f9900d9e10acc40cb602bfdc4f4989b379943cf763cbe36bf87e92
font_01_sfnt_off0000c8d7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC8D7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000e0e9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE0E9 15364 bytes
SHA-256: ee54b3afd0511335d9f78996200a531ba76d7e20707ef865601ceb727d5d88e6

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