Malicious PDF — malware analysis report

Static analysis result for SHA-256 51a1248edb46965d…

MALICIOUS

PDF

81.5 KB Created: 2021-07-14 06:52:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 31e2af3c8b09b824dc8901e6c46428de SHA-1: ece8611a37d074fe25cb4bb13c55b0e2c2f573f6 SHA-256: 51a1248edb46965d3d0dd5b6ce6425aedf11dc6cca9b403679787dd36a424e73
156 Risk Score

Malware Insights

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

The PDF was flagged by ClamAV as Pdf.Phishing.Trojan and an ML classifier indicated a high probability of maliciousness. Heuristics identified it as a link farm pointing to compromised CMS uploads and disposable hosting, suggesting an attempt to distribute malicious content or phish users. The embedded URLs, while numerous, do not directly indicate a specific malware family but reinforce the malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

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://nguyenvanhuongloc.vn/app/webroot/files/images/pages/files/darewiw.pdf In PDF document text
    • http://www.tsssport.com/wp-content/plugins/formcraft/file-upload/server/content/files/16086bc8c0555b---sufopoxadumuxodisa.pdfIn PDF document text
    • http://psystems.gr/Administrator/uploads/userpics/OutPostImages/files/79093638124.pdfIn PDF document text
    • https://condominiobrisasdelnorte.com/userfiles/file/wasetotawonimomokube.pdfIn PDF document text
    • http://nnk.gr/wp-content/plugins/formcraft/file-upload/server/content/files/160a8cd4fc0e82---38312566119.pdfIn PDF document text
    • https://www.bouldersudbury.org/wp-content/plugins/formcraft/file-upload/server/content/files/160add64a5bafb---kofapunigijonazikewuvel.pdfIn PDF document text
    • http://limobebe.com/userfiles/files/bedadi.pdfIn PDF document text
    • https://xo-sound.ru/userfiles/file/7197441130.pdfIn PDF document text
    • https://akdenizokullari.k12.tr/wp-content/plugins/super-forms/uploads/php/files/a14asbhls2hlb5sl8e826oak5o/26115949402.pdfIn PDF document text
    • http://wardwrightself.com/clients/863644/File/pipufumadafepowes.pdfIn PDF document text
    • https://pakistanchristiancongress.org/userfiles/file/39025209935.pdfIn PDF document text
    • http://abapaposentados.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160bfb83c61fba---13290991255.pdfIn PDF document text
    • https://tasivn.com/upload/ck/files/83141591226.pdfIn PDF document text
    • https://selectwifi.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608a3f3623b05---38056959440.pdfIn PDF document text
    • http://aristosaigonhotel.vn/uploads/files/39801599949.pdfIn PDF document text
    • http://ippinnudon.com/uploads/files/tinupobuledibite.pdfIn PDF document text
    • http://aliceinformaticasrl.com/user/pages/51351566910.pdfIn PDF document text
    • https://medgarlci.com/wp-content/plugins/super-forms/uploads/php/files/ff4596eb6c721b876b0f33141777f9ae/48293892890.pdfIn PDF document text
    • https://anzmrrn.org/wp-content/plugins/formcraft/file-upload/server/content/files/1606cc4ea550ed---jobufinonekesonekotade.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/1xuhb7AK25c/uplcv?utm_term=minecraft+pe+seus+shaders+downloadPDF 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_off0000cc5a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCC5A 10896 bytes
SHA-256: 9058e39b683f24128423c54125acd3336900182587392e1ae869805d91066a56
font_01_sfnt_off0000e58e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE58E 23820 bytes
SHA-256: b0d331ef93f9b222f340a5b940c0c6e5172b9bb4de7cd2db4f103efbd36787f2
font_02_sfnt_off000120e2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x120E2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1