Malicious PDF — malware analysis report

Static analysis result for SHA-256 cb5631e528df9caf…

MALICIOUS

PDF

82.7 KB Created: 2021-09-19 02:54:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 4bbdd8139bddca236514051e66947d25 SHA-1: bbc47db97308076123a7073078cd85205c9fd96a SHA-256: cb5631e528df9caf17bed81c488444fc6c1b2bc7b4448d2369b4be8b387be710
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous links, many pointing to compromised WordPress sites and other domains hosting PDF files, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware delivery. The file's structure and numerous external links are consistent with a malicious document used as an initial vector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://ckfinder.pamlskovnik.cz/ckfinder/userfiles/files/pibewe.pdf In PDF document text
    • http://koryosushi.com/uploads/files/73102029078.pdfIn PDF document text
    • http://arsvet.ru/img/upload/gobevivomejavefodev.pdfIn PDF document text
    • https://trompis-tondschungel.de/userfiles/file/82363934809.pdfIn PDF document text
    • http://kagoshimakojintaxi.com/userfiles/file/94516499082.pdfIn PDF document text
    • http://www.mtpartnersfl.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612ee2a1cf518---limoduguvagesovagitimegu.pdfIn PDF document text
    • http://mfplus.ba/wp-content/plugins/formcraft/file-upload/server/content/files/16135daf37c066---riwuxed.pdfIn PDF document text
    • http://www.novosib-sport.ru/ckfinder/userfiles/files/zarenaxemelujasawewazoli.pdfIn PDF document text
    • https://www.barrau-philippe-sedeco.fr/ckfinder/userfiles/files/dobuwubapovimelaxenuzog.pdfIn PDF document text
    • https://manpowernepal.net/ckfinder/userfiles/files/94752861853.pdfIn PDF document text
    • http://sva-jeanroze.com/xmedia/file/kazoganemo.pdfIn PDF document text
    • https://shoppe.everybodyisnotdoingit.org/gift/userfiles/files/jevifogev.pdfIn PDF document text
    • https://bentzendesign.se/wp-content/plugins/formcraft/file-upload/server/content/files/16132fe3180f79---46578754961.pdfIn PDF document text
    • https://spheresignal.com/app/webroot/userfiles/files/jefodizuxudodadizosonu.pdfIn PDF document text
    • http://1day2night.com/UserFiles/file/fibemum.pdfIn PDF document text
    • http://meyergarden.com/ckfinder/userfiles/files/22619616142.pdfIn PDF document text
    • https://imapcb.org/wp-content/plugins/super-forms/uploads/php/files/e6afcf4306e276c5166706973d45664c/jukelusid.pdfIn PDF document text
    • https://iva-vietnam.com/userfiles/file/pakixefepajiravebovuvarup.pdfIn PDF document text
    • https://qfuse.it/images/uploaded_files/ckfinder/files/1631538787_ba88b79035.pdfIn PDF document text
    • http://pkynfe.net/userfiles/file/8589719719.pdfIn PDF document text
    • https://scalper.ir/data/files/file/kidaganu.pdfIn PDF document text
    • https://www.keystonecare.co.uk/wp-content/plugins/super-forms/uploads/php/files/5cf73d1c9475a7d3a52d8ebbac7f5e30/95800341678.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/zMnd8XtcwSM/uplcv?utm_term=bo3+fire+staff+codePDF 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_off0000e012.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE012 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f829.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF829 10544 bytes
SHA-256: 7bd3168130fd2a5a84632240770717e672f0e4294eba99a1e1f72df3bc6a2974
font_02_sfnt_off00011061.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11061 17428 bytes
SHA-256: c8cc161bf74a12e1d0b1b33307049b8d4daafd0abf15f799386773be4a5bf867

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