Malicious PDF — malware analysis report

Static analysis result for SHA-256 8731ed5533987fa7…

MALICIOUS

PDF

79.5 KB Created: 2021-09-09 13:33:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: d063a059112d15a411a6dc0a6d69b604 SHA-1: 5711a85d4c8d9c1f597724d4689fbce5aae59b65 SHA-256: 8731ed5533987fa73ae610259241b3629e3797bfd1fae18f007700641f93b35d
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 CMS upload directories or disposable hosting, indicating a link farm designed to distribute malicious content. The ClamAV detection and ML classifier strongly suggest a malicious intent, likely phishing or malware delivery. No scripts were extracted, but the structure and URL patterns are indicative of a malicious PDF.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

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://upbilbao.com/ckfinder/userfiles/files/kepimejajek.pdf
    • http://bestbelly.org/content/files/files/66967532016.pdf
    • http://www.investing-in-women.com/wp-content/plugins/formcraft/file-upload/server/content/files/161373198d5145---rapanajizajabi.pdf
    • https://solarconsulting.org/wp-content/plugins/super-forms/uploads/php/files/a739b363f3ec97c2209253f0023e4418/jigutazizapozam.pdf
    • http://origo.ws/userfiles/file/35469061319.pdf
    • http://medical-1669.com/userfiles/files/64191521348.pdf
    • http://tokyosushilohaus.com/uploads/files/69432549369.pdf
    • http://buzmakov-ua.ru/admin/ckfinder/userfiles/files/veteg.pdf
    • http://agavietnam.com/img/files/87963139437.pdf
    • https://wct.goldcrownresort.com/magazine_files/files/risogulivirakuxatilikefo.pdf
    • https://dbjadow.pl/attachments/file/gomikupumalajufuzine.pdf
    • http://vaness-sens.fr/ckfinder/userfiles/files/5155244719.pdf
    • https://www.birdandwildlifeteam.com/wp-content/plugins/formcraft/file-upload/server/content/files/161329c7a0291c---51685775463.pdf
    • https://economiadecomunion.com/ckfinder/userfiles/files/zivefegulegisobaji.pdf
    • http://actionelectric.pt/www/wp-content/plugins/formcraft/file-upload/server/content/files/16133d592e8cc0---60236904196.pdf
    • https://olterus.com/contents/files/kikuxug.pdf
    • https://okinawa4d.com/contents/files/ropuwajuwavumasuv.pdf
    • http://tavaszitura.eu/userfiles/files/tiberu.pdf
    • http://suriyedostlukdernegi.org/image/files/6058843040.pdf
    • http://suachuamaydemtien.biz/userfiles/file/23446092087.pdf
    • http://ageddfjtj.pretty-match.com/upload/files/38037697189.pdf
    • http://lsneotek.com/ckupload/files/65810087772.pdf
    • http://mega-stainlesssteel.com/uploads/image/files/36781937395.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BvfzZFkJO3s/uplcv?utm_term=naira+marley+new+song
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d3f5.bin
4aeee709a23f3b3e84b1ce97b2ddd569297618868aee88761ea514fc940077ed
pdf-font-stream PDF embedded font (sfnt) at offset 0xD3F5 10528 bytes
font_01_sfnt_off0000ebfc.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xEBFC 16792 bytes
font_02_sfnt_off0001040e.bin
9530b86c59a5023ac2b137b31e942bbd93c8adf1b7e9151530e84d1c4b996f12
pdf-font-stream PDF embedded font (sfnt) at offset 0x1040E 17096 bytes