Malicious PDF — malware analysis report

Static analysis result for SHA-256 cfd57228ca4dc6fb…

MALICIOUS

PDF

72.0 KB Created: 2021-09-09 13:04:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 11bbeb5e2ddf3cf1bc97c654bbab7778 SHA-1: 78f32df4690e4785b3cbc991714d08d0b516a451 SHA-256: cfd57228ca4dc6fb599996b7c91a89dae32f5d9ff909ab4bf3d7170198278f37
156 Risk Score

Malware Insights

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

The file is identified as malicious by ClamAV and an ML classifier, with heuristics indicating it functions as a link farm. Several URLs extracted from the document point to PDF files hosted on external websites, some of which appear to be compromised CMS uploads. The presence of these links suggests an attempt to lure users to malicious content or exploit SEO vulnerabilities.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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 http://signexpowholesale.com/project-new/christianbook/upload_images/file/sobanunepop.pdf In PDF document text
    • http://az4group.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16133b0c4621b8---16424436634.pdfIn PDF document text
    • http://bestorkate.com/uploads/ckeditor/files/kezufe.pdfIn PDF document text
    • http://nc-israel.ru/upload/files/fogokigirexorekexamafoge.pdfIn PDF document text
    • https://areopag.ru/sites/default/files/uploads/powigozufixuxobopid.pdfIn PDF document text
    • http://elturo.ru/img/upload/files/54378648617.pdfIn PDF document text
    • https://www.cdscabling.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16136378b98aba---wepor.pdfIn PDF document text
    • https://kurishupally.org/userfiles/file/94804835023.pdfIn PDF document text
    • http://beautybybelief.com/admin/images/file/witej.pdfIn PDF document text
    • https://ctners.com/ckfinder/userfiles/files/kilifofopivatikif.pdfIn PDF document text
    • http://luckyassessoria.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/161396e29a1373---84027394423.pdfIn PDF document text
    • https://appchecar.com/ckfinder/userfiles/files/65365474470.pdfIn PDF document text
    • https://accesoriosalmayor.com/images/userfiles/file/79436873725.pdfIn PDF document text
    • https://projektovanje.info/userfiles/file/tetixapipe.pdfIn PDF document text
    • https://oncallanatomist.org/ckfinder/userfiles/files/wenop.pdfIn PDF document text
    • https://lllk.ru/wp-content/plugins/super-forms/uploads/php/files/8e06883bc39186de2f5dde4490de5d12/53808728164.pdfIn PDF document text
    • http://steakclubhn.com/campannas/file/sozarosumuguvazunu.pdfIn PDF document text
    • https://www.hippocratio.gr/ckfinder/userfiles/files/61704286902.pdfIn PDF document text
    • https://fobh.net/userfiles/files/jenifemu.pdfIn PDF document text
    • http://xn--80aa5alfu.kz/file/zewevusopu.pdfIn PDF document text
    • http://0vote.com/ckfinder/files/83195072468.pdfIn PDF document text
    • http://nitexprofi.cz/userfiles/file/61683919153.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/YTWXjIUwRh0/uplcv?utm_term=how+to+clear+search+history+on+your+phonePDF 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_off0000b871.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB871 16124 bytes
SHA-256: e8bcb250bda5da23d58a670e5a9f2cd515b8e9392a5cc94160275592b74b4abc
font_01_sfnt_off0000e1d6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE1D6 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f9ed.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF9ED 10764 bytes
SHA-256: df4a67c4e6c76035bf5bd9fd8d0109833a6bae6875da9f63811915b1b098685c