Malicious PDF — malware analysis report

Static analysis result for SHA-256 cb0c3b1e9ec21bf6…

MALICIOUS

PDF

70.0 KB Created: 2021-09-28 09:06:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 7c7801ebccb7bcdc1876bf9518a4a88c SHA-1: 4f8e47ac02cf81c0ad941b361f010154cbc9e19a SHA-256: cb0c3b1e9ec21bf65f42e8a16c8a41c3d099a466f80d46e196642f74ef740064
156 Risk Score

Malware Insights

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

The PDF contains numerous external URIs and is identified as a link farm, with many links pointing to disposable hosting or compromised CMS uploads. The ClamAV detection and ML classifier strongly indicate malicious intent, likely for phishing or malware distribution by luring users to external sites. No scripts were extracted, and the document body was unreadable, but the heuristic findings are sufficient to assess the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9893

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://chcial.ru/uplcv?utm_term=the+intelligent+investor+by+benjamin+graham+pdf
    • http://xperion.hu/wp-content/plugins/super-forms/uploads/php/files/2adbaf2877b79b7dfce02ce6cbe94831/bugawekowuzogepobu.pdf
    • http://esistore.com/userfiles/file/15363489062.pdf
    • http://school19-zav.ru/userfiles/file/bigudolokofebeserigo.pdf
    • https://www.prowallpanama.com/wp-content/plugins/super-forms/uploads/php/files/3b023f9981a0d04dffd6e69cb2d5af3f/powozumim.pdf
    • http://aweibel.com/Photo/file/58203145970.pdf
    • http://crm333.com/documentos/file/89317564844.pdf
    • http://abwnickersonplaza.com/uploads/files/15907987473.pdf
    • https://procogs.com/FCKeditor/file/79251816912.pdf
    • http://minhphucvietnam.com/uploads/userfiles/file/visida.pdf
    • http://sunriverps.com/data/editor/file/74196646560.pdf
    • https://spitalmoldovanoua.ro/ckfinder/userfiles/files/tofafunazodikor.pdf
    • http://pensjonatagat.pl/userfiles/file/16624879816.pdf
    • https://rhuyscampingcar.fr/images/files/62727039704.pdf
    • https://hgqq.hk/tony/churchofgod/ckfinder/userfiles/files/riranaxim.pdf
    • http://xn--h1agcmh.com/ckfinder/userfiles/files/bogubikiregolaka.pdf
    • https://sofupingame.com/calisma2/files/uploads/69049463874.pdf
    • https://hunde-katzen.at/soubory/25706854018.pdf
    • https://iamluno.com/wp-content/plugins/formcraft/file-upload/server/content/files/16133fd067208a---komubilakodit.pdf
    • https://ctners.com/ckfinder/userfiles/files/zavod.pdf
    • http://www.expo-hotel.com/english/wp-content/plugins/formcraft/file-upload/server/content/files/16140e696f38ee---letulesowid.pdf
    • http://eng.sut.ac.th/tce/2016/administrator/ckfinder/userfiles/files/marutoxidodasetubi.pdf
    • https://aiaciran.org/cache/fck_files/file/86929344461.pdf
    • https://htchninc.com/d/files/94799839731.pdf
    • http://longarmquiltacademy.net/fckeditor/userfiles/file/bazetesonutexum.pdf
    • https://hantverkarenisandby.se/UserFiles/files/siwewalevutopedemur.pdf
    • https://adproissy.emailingmanager.com/uploads/editor/file/84862161390.pdf
    • 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_off0000b2d7.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xB2D7 16792 bytes
font_01_sfnt_off0000caee.bin
42046f64e1a7a0838aff2cd515f78c737ba133e9000bfa3f20c35350b9cc751e
pdf-font-stream PDF embedded font (sfnt) at offset 0xCAEE 11360 bytes
font_02_sfnt_off0000e509.bin
a08331c23ae8ae61e8c568fe117f36dad69d5689fafa31f844a19a3a46e4a8b2
pdf-font-stream PDF embedded font (sfnt) at offset 0xE509 14736 bytes