Malicious PDF — malware analysis report

Static analysis result for SHA-256 85cd4ced4654d1f1…

MALICIOUS

PDF

95.8 KB Created: 2021-08-09 14:42:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 910a1ce2abb7be23ad5ac31d6d1d2415 SHA-1: b6a540659402022bb647cc5647fd84a90284199b SHA-256: 85cd4ced4654d1f1e61b1110eecad4e8ef504fff7a7ddd8dcf0fd147d8ef79ec
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm, with many URLs pointing to compromised WordPress upload directories and disposable hosting. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather to host links. The primary attack pattern involves directing users to potentially malicious external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

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://mkting.com.co/wp-content/plugins/super-forms/uploads/php/files/92ca6242e424d80f8323a8d725b5aee6/mexafatowekukif.pdf In PDF document text
    • https://spencershaulageltd.co.uk/wp-content/plugins/super-forms/uploads/php/files/e285caf90e2f96492dea216c59a21d14/jafijirazokegejelusega.pdfIn PDF document text
    • http://bolshunoff.ru/images/wysiwyg/file/pesojujokojo.pdfIn PDF document text
    • http://ahcxdq.com/uploads/file/151054487275.pdfIn PDF document text
    • http://archinfo.ru/uploads/file/9058480175.pdfIn PDF document text
    • https://gbagencement.fr/uploads/file/davelosawojixakiperagux.pdfIn PDF document text
    • https://www.euroservicemilano.it/wp-content/plugins/formcraft/file-upload/server/content/files/160bf04268f5e0---jejunavevojumabupikadof.pdfIn PDF document text
    • http://grupopiscis.com/upload/files/jokilelejepu.pdfIn PDF document text
    • https://luyenthitoeic.info/userfiles/file/nuzuwabugerololotin.pdfIn PDF document text
    • http://birons.net/wp-content/plugins/super-forms/uploads/php/files/c684e3c038fb749abe6cf1678c10d73d/79425826200.pdfIn PDF document text
    • http://www.thebetterinsurance.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608963f0b6d6c---4853253724.pdfIn PDF document text
    • http://yesilkoyluleriz.biz/resimler/files/ziler.pdfIn PDF document text
    • https://harpethvalleypto.org/wp-content/plugins/super-forms/uploads/php/files/234a35ca15872c1cc1cf46beb239d51b/74837330661.pdfIn PDF document text
    • http://www.gpkoaee.ru/ckfinder/userfiles/files/lesavaniba.pdfIn PDF document text
    • http://drinkandshrink.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160c8b18833c7b---lozalidunukakuduni.pdfIn PDF document text
    • https://mma-montessori.com/admin/ckfinder/userfiles/files/11394545324.pdfIn PDF document text
    • https://discovercefalu.com/_data/images/file/94491930955.pdfIn PDF document text
    • http://iworking.vn/uploads/files/kilozigepibodenowezira.pdfIn PDF document text
    • http://www.cenlajobinator.com/siteuploads/editorimg/file/96785774799.pdfIn PDF document text
    • http://trans-serwis.com/userfiles/file/6788336587.pdfIn PDF document text
    • http://kfnmdg.com/upfolder/e/files/20210714131548.pdfIn PDF document text
    • https://loskutova.site/wp-content/plugins/super-forms/uploads/php/files/7208e4a847a509053d81172f019b437a/87366718217.pdfIn PDF document text
    • http://ilovehikari.com/uploads/files/wuwetot.pdfIn PDF document text
    • http://cfacgroup.com/uploads/FCK_files/file/fulamubunuxaxat.pdfIn PDF document text
    • https://rent-1.es/ckfinder/userfiles/files/35287805671.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/PmAiG5ZyT-k/uplcv?utm_term=can+we+workout+during+gm+dietPDF 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_off0001164a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1164A 10688 bytes
SHA-256: 7db5b7dd752aa808226800d07a41122cd6edae94fcf5e3c3fcfc5c7f5ff38571
font_01_sfnt_off00012ea2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12EA2 16504 bytes
SHA-256: 7761025732fdc24188b382e93ceb4783a0dfef1fc8583769da93f15bdc498c5a
font_02_sfnt_off000159a3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x159A3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1