Malicious PDF — malware analysis report

Static analysis result for SHA-256 6ac1c3c926c25eec…

MALICIOUS

PDF

79.9 KB Created: 2021-07-30 23:58:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 0f6b2402c8cc4ed172108699f9beecf7 SHA-1: 3b18e87c677dd891bb3eddf00f0f5267c33c2b32 SHA-256: 6ac1c3c926c25eec329e5e51fcea77ee2a80574f2124650c7e859e3f38522ca2
156 Risk Score

Malware Insights

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

The PDF contains numerous external URIs and links to compromised WordPress upload storage, indicating a phishing or malware distribution attempt. The ML classifier and ClamAV detection strongly suggest malicious intent. The document body is heavily obfuscated and appears to be non-readable content generated by wkhtmltopdf, providing no direct user-facing lure.

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://synerhu.ru/uplcv?utm_term=musculos+agonistas+antagonistas+y+sinergistas+pdf
    • http://flygarfield.net/userfiles/file/wirazivalu.pdf
    • https://unitedcardsolutions.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a7b74324c04---13283760422.pdf
    • http://sun-tes.ru/files/file/567272418.pdf
    • https://michaels-limo.com/wp-content/plugins/formcraft/file-upload/server/content/files/160acccfed5ac4---nukewupoxagage.pdf
    • https://travelinnsuites.com/nbloom/fckuploads/file/semijubujamusolaruluwel.pdf
    • https://www.alapan.org/fckimages/file/lefiwaneranawiz.pdf
    • http://scenekunstskolen-efteruddannelsen.dk/ckfinder/userfiles/files/diwobugalivareg.pdf
    • http://www.redactordecontenidos.eu/wp-content/plugins/formcraft/file-upload/server/content/files/160a29bed0eac1---43463770068.pdf
    • http://szguilong.com/userfiles/files/12789212095.pdf
    • http://bilagroup.com/wp-content/plugins/formcraft/file-upload/server/content/files/16090ffebb5ead---26825191610.pdf
    • http://smithmurdock.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607c56d70c103---30122830215.pdf
    • https://amenagementsoleil.com/wp-content/plugins/formcraft/file-upload/server/content/files/160926a7f19fd7---seluxosomokowekikurujeko.pdf
    • https://nscs.org/wp-content/plugins/super-forms/uploads/php/files/5ff80b3273f0ff936d274627e282fa38/8619818719.pdf
    • https://www.ptlittleflower.org/wp-content/plugins/super-forms/uploads/php/files/sb90c3q4tub347t6emisbuahed/dameruvikuxisenalupogova.pdf
    • https://masterjobintl.com/ckfinder/userfiles/files/kisaxiw.pdf
    • http://jfkanacon.org/data/userfiles/files/28883618648.pdf
    • http://braintradingbcn.com/wp-content/plugins/super-forms/uploads/php/files/5cf98e5baf1265e315f7f392116bfd4d/zisut.pdf
    • https://daleel.global/wp-content/plugins/super-forms/uploads/php/files/dbaqfqohoess179d9kda7qdtp6/1802849677.pdf
    • https://palcev.ru/userfiles/file/lebosube.pdf
    • http://akbmodel.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606fc29ebcd08---piminale.pdf
    • https://encouragingmath.com/wp-content/plugins/super-forms/uploads/php/files/0352a858b55747005224ff7b6c1161b1/78230982556.pdf
    • https://xosobacninh.vn/webroot/img/files/xabasinejasenukozimuwege.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_off0000d40c.bin
a5f04605c880b06cb73d29aa1bd1232b0e63999bde2328b3e0878da54050990d
pdf-font-stream PDF embedded font (sfnt) at offset 0xD40C 11000 bytes
font_01_sfnt_off0000ed99.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xED99 16792 bytes
font_02_sfnt_off000105ab.bin
c6eb8a7911f49a2dbb18ccf6f25aa3cae1edb1bf9ad08b4ebf2221e296c0e049
pdf-font-stream PDF embedded font (sfnt) at offset 0x105AB 17356 bytes