Malicious PDF — malware analysis report

Static analysis result for SHA-256 7c7751b88ab877f9…

MALICIOUS

PDF

81.0 KB Created: 2021-09-01 16:55:51 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 6e724d6161f87efdefd7b4cc76b9892d SHA-1: 2c38e0dd940f72b9a8761c97006caadbb315a08e SHA-256: 7c7751b88ab877f90d0be65f76de76a06692b06c1a40fa5e9bff9db348dc505d
156 Risk Score

Malware Insights

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

The PDF contains a large number of embedded URLs, many of which point to compromised WordPress sites and disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or to redirect users to further malicious content. The document body is heavily obfuscated and unreadable, providing no direct textual clues, but the heuristic firings and URL analysis are sufficient to determine the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9972

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://snabavto.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c2a11e5bd79---76154776217.pdf In PDF document text
    • http://domingo.hu/ckfinder/userfiles/files/romukuramuxumizoruvarovi.pdfIn PDF document text
    • https://celebicatering.com/upload/ckfinder/files/gumifosoxifazufaxanimeba.pdfIn PDF document text
    • http://www.salac.cz/ckfinder/userfiles/files/16433011278.pdfIn PDF document text
    • http://www.agrosystem.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/160ad921e5dda7---mopuz.pdfIn PDF document text
    • https://nikosdimos.gr/userfiles/file/63066075252.pdfIn PDF document text
    • http://tokstar.com/_UploadFile/Images/file/pamosikikeg.pdfIn PDF document text
    • https://mrmusicfoundation.org/wp-content/plugins/super-forms/uploads/php/files/4eg90hji3ue9mq5loilun58eun/rejimeki.pdfIn PDF document text
    • http://gf-location.fr/wp-content/plugins/formcraft/file-upload/server/content/files/160aab41bd279b---dabasukawegafaza.pdfIn PDF document text
    • https://stepweystudy.com/ckfinder/userfiles/files/bavuretajakovenugudop.pdfIn PDF document text
    • https://my-natural-style.net/upload/files/munavono.pdfIn PDF document text
    • http://cjcounsel.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/33942491488.pdfIn PDF document text
    • https://maisonforville.be/documents/file/mobiramizomowugokibidided.pdfIn PDF document text
    • https://www.advids.co/wp-content/plugins/formcraft/file-upload/server/content/files/160adc5908dd11---zulimunozolagak.pdfIn PDF document text
    • https://www.physioaktivkramer.de/wp-content/plugins/formcraft/file-upload/server/content/files/160fe619cae8d8---vumetejapinosiw.pdfIn PDF document text
    • https://corghialberti.it/file/79095732381.pdfIn PDF document text
    • https://nailseasupportgroup.com/wp-content/plugins/super-forms/uploads/php/files/c62b2ccfd1fd357adc4f5d71c1d7dea7/61823640815.pdfIn PDF document text
    • https://c4ir.ae/wp-content/plugins/super-forms/uploads/php/files/sac1o345d9jv05eedca4rvk367/mijikirigi.pdfIn PDF document text
    • https://mokhalasati.com/userfiles/files/38812971249.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e33876d349a---dukepepidejigelu.pdfIn PDF document text
    • https://binarbaidfabrication.com/public_html/userfiles/file/37508749475.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/A3Ryygt5BCM/uplcv?utm_term=frcp+class+actionPDF 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_off0000d93c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD93C 10212 bytes
SHA-256: 322acd3370228832a2608696d9c6d7406853af3af7752ebaa060d33e6a68cf8b
font_01_sfnt_off0000f032.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF032 18248 bytes
SHA-256: b8f1cf86f3e3a4c2827054fa60c3298025d3689d0dcd19581cec33dc4bf61097
font_02_sfnt_off00011f55.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11F55 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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