Malicious PDF — malware analysis report

Static analysis result for SHA-256 b23ca707018f1dfe…

MALICIOUS

PDF

68.0 KB Created: 2021-09-29 07:58:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 8c3c1a2720ca372029de00f401588ab8 SHA-1: 085d4863b8c5e19461f607038152184f40916721 SHA-256: b23ca707018f1dfe8c6c5ac90f587561e49dac8831083b36b66ab81a1226d131
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 disposable hosting, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware delivery through these links. The document body is unreadable, but the heuristic firings and URL analysis are sufficient to determine the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9957

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 http://artwatch.ru/userfiles/file/54192187176.pdf
    • http://bacsiha.com/public/ckfinder/userfiles/files/dikarexuguferubufetoj.pdf
    • http://lookupagency.es/wp-content/plugins/formcraft/file-upload/server/content/files/1615100a74b46e---52463872757.pdf
    • http://pphu-joanna.pl/fckpliki/file/56281572951.pdf
    • https://cherrychile.cl/cherry/uploads/contenido/files/52284714950.pdf
    • http://leebyenghun.com/new/upload/board/files/67979959398.pdf
    • https://wita.lt/images/files/donozami.pdf
    • https://eletmodguru.hu/files/files/71318864994.pdf
    • https://strefaokazji.pl/uploaded/file/tubupekuledut.pdf
    • https://www.ideaklinikbakirkoy.com/wp-content/plugins/formcraft/file-upload/server/content/files/16137ff708af40---10107775089.pdf
    • http://timatey.kz/wp-content/plugins/super-forms/uploads/php/files/hnbrb69d5ffn772b80c4aniku1/zalawuxutozifesage.pdf
    • http://xn--80ab1a9a.xn--p1ai/sadm_files/16981719584.pdf
    • http://bobas24.pl/Upload/file/madoripabasi.pdf
    • http://kuppersbusch.hu/userfiles/files/fugepenevezevifuwovef.pdf
    • http://poney-club-romilly-aigre28.fr/userfiles/file/xadutapero.pdf
    • http://entrackintl.com/uploads/monofoxagopibogufe.pdf
    • http://horizonpestservices.com/userfile/vaxabajete.pdf
    • http://onsijsselstein.nl/userfiles/files/21573326401.pdf
    • http://inimtrento.it/userfiles/files/47495033844.pdf
    • http://nhatminhtrading.vn/app/webroot/uploads/files/dewaroditiruro.pdf
    • http://support-cmu.com/filedata/file/54689159762.pdf
    • https://www.teppiche-waschen-hamburg.de/wp-content/plugins/formcraft/file-upload/server/content/files/1614f5d993443d---75420741539.pdf
    • http://ttworld.hu/uploads/content_files/files/xesidal.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/3CAf4wW3hvY/uplcv?utm_term=mlb+9+innings+21+apk
    • 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_off0000add4.bin
b19679956ced1c93dc8019a74839eccddb116f0a94123e02ad33a32ad8a45b1c
pdf-font-stream PDF embedded font (sfnt) at offset 0xADD4 10540 bytes
font_01_sfnt_off0000c5cb.bin
6299bc0116b13f2e007a3c996db16163ff168fa81f96e50fd31f144322e39dc6
pdf-font-stream PDF embedded font (sfnt) at offset 0xC5CB 14800 bytes
font_02_sfnt_off0000ead0.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xEAD0 16792 bytes