Malicious PDF — malware analysis report

Static analysis result for SHA-256 6fbdb1568d95b098…

MALICIOUS

PDF

74.0 KB Created: 2021-06-13 16:34:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 87b4637dd3c0b9eb27661ff9a83cdfb5 SHA-1: 77ad90548a206ba92ada36af73b50889a26fcb19 SHA-256: 6fbdb1568d95b0980ba10426339079b79ed7a8c141c0220f141ce6dd9a12cf91
156 Risk Score

Malware Insights

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

The PDF contains numerous external links, many pointing to compromised WordPress sites, suggesting a link farm designed to redirect users to malicious content. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution. The document body is heavily obfuscated and contains metadata indicating it was generated by wkhtmltopdf, a tool often used to create PDF versions of web pages, further supporting the link farm hypothesis.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://pistant.ru/uplcv?utm_term=read+one+punch+man+chapter
    • http://cedresarquitectura.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608871fa90301---nejafufapuj.pdf
    • https://tkquiz.com/userfiles/file/55269045593.pdf
    • https://www.d-table.com/wp-content/plugins/super-forms/uploads/php/files/753bf6601212dfb1981425bd2d819862/xuzivibokogepekotigex.pdf
    • https://sarujiovalente.com/wp-content/plugins/super-forms/uploads/php/files/doi0v3uljs97hom4ogp6qnvcuj/fokovevolufi.pdf
    • https://polskieplytki.com/wp-content/plugins/super-forms/uploads/php/files/f5450378464fa503e5e6885bf9694633/gajuwixa.pdf
    • http://21cedu.com/pds/userfiles/files/xusedepijabesugafoxolilu.pdf
    • http://grupogmec.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ba0de00cb2b---38374027089.pdf
    • https://amalighting.com/wp-content/plugins/super-forms/uploads/php/files/43de956cfe2f6ea03610fd893a5b4f28/xasikira.pdf
    • https://christianboudreau.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ae3282bb297---joxusaz.pdf
    • https://www.lipfish.no/wp-content/plugins/formcraft/file-upload/server/content/files/1609ce9eb667ca---lefopisopab.pdf
    • https://kermoulin.com/userfiles/file/26076887170.pdf
    • http://voxel-avocats.fr/uploads/file/85827831692.pdf
    • http://hillsdalehorseboarding.com/ckfinder/userfiles/files/78984409640.pdf
    • https://amagi.la/wp-content/plugins/formcraft/file-upload/server/content/files/160a4d73b25190---57159946080.pdf
    • https://www.pferde-fuer-unsere-kinder.de/wp-content/plugins/formcraft/file-upload/server/content/files/1609aa2607bb4b---durulilanakotibu.pdf
    • http://aep-tc.com/cache/fck_files/file/5672869278.pdf
    • http://www.meglobalinc.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/16099b17f9f431---76596780947.pdf
    • http://araonline.hu/uploads/file/26620177626.pdf
    • http://sobsai.com/ckfinder/userfiles/files/86602744754.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • 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://scripts.sil.org/OFL

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d9ec.bin
fd44b99cd4641fda623594e71c3124a05f24db83c795b817ec8cecdc2c4ac2a3
pdf-font-stream PDF embedded font (sfnt) at offset 0xD9EC 3532 bytes
font_01_sfnt_off0000e68c.bin
8c545e5f95991b3558a0c2f45d33c9838c4d18943d22655fa157986179732d82
pdf-font-stream PDF embedded font (sfnt) at offset 0xE68C 5108 bytes
font_02_sfnt_off0000f7c8.bin
e7774b5c9d2e3cd40d64c1bcf54f856e67e25379d50b227bdfd050250d87aef4
pdf-font-stream PDF embedded font (sfnt) at offset 0xF7C8 9692 bytes