Malicious PDF — malware analysis report

Static analysis result for SHA-256 ca66f24ac9ed313c…

MALICIOUS

PDF

69.2 KB Created: 2021-09-27 04:16:30 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 517e2fa342593d2c3b70a84cf58d2605 SHA-1: 0f3387f4554b750cfcb9816781e1e66f52097537 SHA-256: ca66f24ac9ed313c385b93fc7cf8bcc12d90a62acfb6ad1af285fe5a997557e0
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised websites or are part of a link farm designed to obscure the final destination. Heuristics indicate these links are likely used for phishing or to distribute malware, as suggested by the ClamAV detection and ML classifier flagging it as malicious. The document body is unreadable, but the overall structure and URL analysis strongly suggest a malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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=9+class+social+textbook PDF link annotation
    • http://guanzhuli.com/userfiles/file/8930980156.pdfIn PDF document text
    • http://artgrafika.cz/userfiles/file/75980311714.pdfIn PDF document text
    • http://fosterfreezesantarosa.com/uploads/files/kavizobulanadowuburixo.pdfIn PDF document text
    • http://pokrowce-ochronne.pl/Upload/file/38179494210.pdfIn PDF document text
    • https://santa.sg/images/users/00000000/files/20130296323.pdfIn PDF document text
    • https://tele-video.ru/upload/files/pugevanaxurowemubofe.pdfIn PDF document text
    • http://bjqyms.com/filespath/files/20210903184231.pdfIn PDF document text
    • http://www.pointcookelectrician.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1613d7fb10f49d---tojiwimewelig.pdfIn PDF document text
    • https://penzehir.com/dorceiys/ckfinder/userfiles/files/madodaj.pdfIn PDF document text
    • https://360clothing.in/home/www360cl/public_html/uploads/images/files/zaseju.pdfIn PDF document text
    • http://serbanindustrialconstruct.ro/uploads/files/94348614882.pdfIn PDF document text
    • http://www.psstrecno.sk/wp-content/plugins/formcraft/file-upload/server/content/files/161425eee999c1---96678908984.pdfIn PDF document text
    • http://ibookingkr.com/FileData/ckfinder/files/20210916_900CC6C33D12AD3D.pdfIn PDF document text
    • http://klick-tipp.info/ckfinder/userfiles/publics/files/kemudukujulokof.pdfIn PDF document text
    • http://ivelinabozilova.com/userfiles/file/nepin.pdfIn PDF document text
    • https://cms.blauraum.com/wp-content/plugins/super-forms/uploads/php/files/d720b41a8e3b12fb70bea81387554317/sodakuzubaruxowetuwe.pdfIn PDF document text
    • http://www.frank-diagn.hu/userfiles/files/daralanoj.pdfIn PDF document text
    • https://namphuctourist.com/userfiles/file/3071315878.pdfIn PDF document text
    • http://ucinnovation.ru/admin/ckfinder/userfiles/files/89946240769.pdfIn PDF document text
    • http://flyingfish-stay.com/userfiles/file/46479469547.pdfIn PDF document text
    • https://optimustelecoms.com/ckfinder/userfiles/files/53049927478.pdfIn PDF document text
    • http://kangshi-you.com/uploads/files/202109052314231581.pdfIn PDF document text
    • https://alkalacarservice.com/public_html/userfiles/file/gekab.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_off0000af09.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAF09 15876 bytes
SHA-256: b6d52e0768e298fd294ad7cbf1faab763e256545f45f42a14b9cd2e61fb2dd01
font_01_sfnt_off0000d7de.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD7DE 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000eff5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEFF5 10424 bytes
SHA-256: 3462a22b3ae90053b97dd03ff08f70cd3e344047c4cf18d774171090a2912fc3