Malicious PDF — malware analysis report

Static analysis result for SHA-256 4cb9f6858b167f1e…

MALICIOUS

PDF

82.2 KB Created: 2021-09-16 05:37:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 72b71c43705a1ff0e5106ff4b347138d SHA-1: 66a5643fbb9349f24da0a03080eb337fb4768517 SHA-256: 4cb9f6858b167f1e4e22fefa493384ddb801edcd2ca61adbac3ccd93db7cf309
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous embedded URLs, many pointing to compromised WordPress sites or disposable hosting, suggesting a link farm designed to redirect users to malicious content. The presence of PDF-specific heuristics like 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' and 'PDF_SEO_DISPOSABLE_LINK_FARM' further supports this. While no scripts were explicitly extracted, the nature of the embedded links and the overall structure point towards a phishing or malware distribution scheme, likely initiated via spearphishing.

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://aldea.work/wp-content/plugins/super-forms/uploads/php/files/6a55fcadfa335b177a18241b368bcb83/69940120558.pdf In PDF document text
    • https://sieseam.org/userfiles/files/folibenumaz.pdfIn PDF document text
    • http://nuyewpilot.academy/wp-content/plugins/super-forms/uploads/php/files/070c8f80a173829bb42fcc4676727143/risijivopodi.pdfIn PDF document text
    • https://blv.by/upload/editor/files/bewasozuwifi.pdfIn PDF document text
    • http://narcisse.sk/editor_uploads/files/94599562378.pdfIn PDF document text
    • https://inprovitperu.com/ckfinder/userfiles/files/kovomanafek.pdfIn PDF document text
    • http://libertyquad72.fr/userfiles/file/petetixarikozo.pdfIn PDF document text
    • http://www.eflox.net/wp-content/plugins/formcraft/file-upload/server/content/files/1613ebe9d5c0a2---40892731937.pdfIn PDF document text
    • http://cdseoulps.com/uploadfile/fckeditor/file/79740502621.pdfIn PDF document text
    • http://accessiblevehicleservices.com/userfiles/file/towegukota.pdfIn PDF document text
    • https://www.nobleorthodontic.com/wp-content/plugins/super-forms/uploads/php/files/60fd43fa1082578bf3606f7aa7c8ce98/nigavugevebug.pdfIn PDF document text
    • https://www.dekleinewerf.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1613ca27eb0444---55987847235.pdfIn PDF document text
    • http://ifaistos.reality.gr/~triantaf/images/file/23956626034.pdfIn PDF document text
    • http://toroisg.com/public/images/files/zuzulefukemujiku.pdfIn PDF document text
    • http://nnk.gr/wp-content/plugins/formcraft/file-upload/server/content/files/161408f7f8957a---rizotekisokol.pdfIn PDF document text
    • https://teplitsyoptom.ru/wp-content/plugins/super-forms/uploads/php/files/5614369bd79e84aa154a04dfc4691fff/bujurebokolexipuzanu.pdfIn PDF document text
    • https://dulsuc.cl/userfiles/file/sobonosezizozaxupu.pdfIn PDF document text
    • http://www.tecs4.com/intranet/ckfinder/userfiles/files/jasiremininog.pdfIn PDF document text
    • http://bebaldebaran.eu/userfiles/files/77320558431.pdfIn PDF document text
    • https://vetregistr.com/ckfinder/userfiles/files/xifopitawawu.pdfIn PDF document text
    • https://sistemagestiondpr.co/userfiles/file/lelukavewotev.pdfIn PDF document text
    • https://kaparatt.com/images/File/15428593188.pdfIn PDF document text
    • https://hagabb.ro/ckfinder/userfiles/files/79817279168.pdfIn PDF document text
    • https://skvely-kup.cz/files/file/pawuxovezewenigepidezen.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/PmAiG5ZyT-k/uplcv?utm_term=dios+vuelve+en+una+harley+pdfPDF link annotation
    • 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_off0000d935.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD935 19288 bytes
SHA-256: e7de97f0e1e86dc4944975200f0dd082386f1ff19ad2929f262406fdb0e082cf
font_01_sfnt_off00010a8a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A8A 10780 bytes
SHA-256: 78e4ea8fce85ff70d28a2a2639c7f1e6e5bc0e5a8cd1a8c862225f52ba93fa37
font_02_sfnt_off00012349.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12349 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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