Malicious PDF — malware analysis report

Static analysis result for SHA-256 c4a62cd1a8400910…

MALICIOUS

PDF

67.9 KB Created: 2021-09-16 07:12:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 1f3345f44bd71397e73efca94b0ab05b SHA-1: d9b37f81569c3384b05ff8df174f2ce141abc270 SHA-256: c4a62cd1a8400910e157dafb1c6f191ce031959a372decc9b10f8bd4883625a8
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF containing embedded JavaScript, which is a common technique for exploiting vulnerabilities or redirecting users. Heuristics indicate it functions as a link farm, pointing to numerous external URLs, some hosted on compromised WordPress sites. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://inwebjor.ru/uplcv?utm_term=my+android+tablet+keeps+freezing PDF link annotation
    • https://ecef-groupe.com/wp-content/plugins/super-forms/uploads/php/files/80kp543s0s99apdod1mhdor634/rumojapifatuwafeluleki.pdfIn PDF document text
    • http://www.espaciocultivarte.com/ckfinder/userfiles/files/27848728692.pdfIn PDF document text
    • https://0a3exp.com/upfiles/editor/files/44054628068.pdfIn PDF document text
    • http://medica-eg.com/userfiles/file/95421780786.pdfIn PDF document text
    • https://cdmsig1.com/ckfinder/userfiles/files/5754385310.pdfIn PDF document text
    • http://anchor-m.com/js/upload/files/vedilamuguvekupe.pdfIn PDF document text
    • http://royalleasingny.com/admin/images/file/40498510713.pdfIn PDF document text
    • http://azizolace.cz/images/file/zidexufosutoxaxax.pdfIn PDF document text
    • http://german-ex.com/images/blog/file/91843661680.pdfIn PDF document text
    • https://genegurumiraclehealer.com/userfiles/file/4107352944.pdfIn PDF document text
    • https://prcomponents.com/ckfinder/userfiles/files/xiluwowuxobujiveva.pdfIn PDF document text
    • http://pileki.com/imgup/file/27411942908.pdfIn PDF document text
    • http://anais.terminarz.online/kosmetyczka/krakow/files/kofofilibogezodunesumur.pdfIn PDF document text
    • https://wamsconference.com/wp-content/plugins/super-forms/uploads/php/files/b8aafbc60bbd867d45268f5d99123193/lusazuvomelovo.pdfIn PDF document text
    • http://zonwering-nederland.com/ckfinder/userfiles/files/76507279298.pdfIn PDF document text
    • http://sakem.org/userfiles/files/wasufopixurakoxiba.pdfIn PDF document text
    • http://www.psoealora.es/ckfinder/userfiles/files/watekopej.pdfIn PDF document text
    • https://www.iieng.org/editor/ckfinder/userfiles/files/17041878921.pdfIn PDF document text
    • https://realimpacto.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16140ce5dc218a---donuru.pdfIn PDF document text
    • http://drumlockingclamp.com/FCK_Editor_Images/files/88249768619.pdfIn PDF document text
    • http://www.adarshvidhyasankul.org/userfilesfile/ruvow.pdfIn PDF document text
    • 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_off0000abb8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xABB8 14784 bytes
SHA-256: 1325cffc77928fedad0f0ca5aaa10e01cca54c8524edd82db87bd5c4883476f7
font_01_sfnt_off0000d0f4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD0F4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000e90b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE90B 11072 bytes
SHA-256: 6f82c5f9fb42b3691d3068e87af38ec170eea18ee8f277d9f57857946bb1d8ff