Malicious PDF — malware analysis report

Static analysis result for SHA-256 87988b6c6ae0fc2b…

MALICIOUS

PDF

81.1 KB Created: 2021-08-24 22:52:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 352b4735751cf34101139a33a4429cf9 SHA-1: faae671bc56341d7a0371a45b9a033e64ef75661 SHA-256: 87988b6c6ae0fc2b6452b8d1b0e13f120c87df53d3ca95529af679988b3b2b1c
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous external links, many pointing to compromised CMS uploads and disposable hosting, suggesting a link farm designed to redirect users to malicious content. The presence of embedded JavaScript, flagged by heuristics, indicates an attempt to execute code, likely to facilitate further malicious activity such as downloading additional payloads or redirecting the user. The ClamAV detection and ML classifier further support the malicious nature of this file.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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://nomylo.ru/uplcv?utm_term=new+inspiration+3+teacher%27s+book+pdf+free+download
    • https://lanna-flyingclub.com/ckfinder/userfiles/files/40425161843.pdf
    • http://www.birapart.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608a9dba1dd97---noxunulinemizari.pdf
    • http://greenmodels.ru/uploads/files/kabumumura.pdf
    • http://distributoram.com/files/file/83140862112.pdf
    • http://dainichiji.com/upload_ckr/files/fipubamelaxi.pdf
    • http://notarbrazda.cz/userfiles/file/lurabolesenabuvavowin.pdf
    • http://diysmart.net/userfiles/file/87152847715.pdf
    • http://www.x454.com/wp-content/plugins/super-forms/uploads/php/files/kj3raeggrfbs6o84t45cthvrh5/74193685358.pdf
    • http://canadapremiumlubes.com/survey/userfiles/files/fediwo.pdf
    • http://www.suffaheducation.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c3623ea17fd---15406869919.pdf
    • https://edoxmarketing.com/wp-content/plugins/super-forms/uploads/php/files/bg7u621f8n5r511v3lm61c8ksl/fipagawarudadozuwib.pdf
    • http://finalstage.biz/js/upload/files/4441937905.pdf
    • http://yaqeen-eg.com/userfiles/file/zirunew.pdf
    • http://slowjamsundays.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a366bf3ce01---finuresidazi.pdf
    • https://fgcrubochi.com.ng/ckfinder/userfiles/files/40561350348.pdf
    • https://cdmsig.com/ckfinder/userfiles/files/46129448341.pdf
    • http://applexin.com/ttpsea/files/file/nafeguvunejumujugup.pdf
    • https://burkina-businessschool.com/business_school/uploads/file/34143369307.pdf
    • http://unesco-mediain.cz/fckfiles/file/70965833931.pdf
    • http://www.johnknox.ch/wp-content/plugins/formcraft/file-upload/server/content/files/160a02e0ad1c74---7409729270.pdf
    • http://praxis-greve-polley.de/web/editor/files/81415471211.pdf
    • http://maroba-zirndorf.de/file/29011345415.pdf
    • https://swotin.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609ec1d414fa2---sapepula.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_off0000cfe4.bin
b9a6ead025ee4a4f296da41d5516708a1038d22ecfa6fc538297024f8c32f4ea
pdf-font-stream PDF embedded font (sfnt) at offset 0xCFE4 20168 bytes
font_01_sfnt_off000101b3.bin
3aff1903bda8be380df91754398eda9284afa912df7166c272227b38a9be6ea6
pdf-font-stream PDF embedded font (sfnt) at offset 0x101B3 11220 bytes
font_02_sfnt_off00011bd3.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x11BD3 16792 bytes