Malicious PDF — malware analysis report

Static analysis result for SHA-256 cc5b96d2f14e0962…

MALICIOUS

PDF

82.0 KB Created: 2021-10-10 11:37:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 3649c125bbc841fe2c4188c01afe66c1 SHA-1: e66ae1ae7e8b975a75c657583306863d7bea7a86 SHA-256: cc5b96d2f14e096265542d87c5b80299866722eb0f64d78897173a88416b3695
156 Risk Score

Malware Insights

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

The PDF contains a link farm pointing to numerous unknown PDF files hosted on compromised websites, as indicated by the 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' heuristics. The ML classifier and ClamAV detection strongly suggest malicious intent, likely to manipulate search engine results or distribute further malware. No scripts were extracted, and the document body was unreadable, so the attack pattern is inferred from the URL structure and heuristic findings.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

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 https://marksiegeldds.com/wp-content/plugins/super-forms/uploads/php/files/32bc18d1cc705e4a3fcc8d0abeefd4bb/joxuka.pdf In PDF document text
    • http://kbidc.kr/upload/editor/file/1630702145.pdfIn PDF document text
    • http://nanobubblevietnam.com/uploads/userfiles/file/7854546296.pdfIn PDF document text
    • http://lishasurgical.in/ckeditor/ckfinder/userfiles/files/rukasobemadijopalugidirew.pdfIn PDF document text
    • http://progfin.pl/userfiles/file/52155288575.pdfIn PDF document text
    • https://oglethorpeclub.org/~oglethor/UserFiles/file/22268707744.pdfIn PDF document text
    • http://cp-1.ru/userfiles/files/gijurusupabim.pdfIn PDF document text
    • https://mkserwis.pl/userfiles/file/42149453612.pdfIn PDF document text
    • https://expomediainc.com/upload/file/kefurovaruv.pdfIn PDF document text
    • http://thevale.us/userimages/59049359448.pdfIn PDF document text
    • http://guides2alpes.fr/uploads/file/42408202795.pdfIn PDF document text
    • https://www.paseppe.gr/ckfinder/userfiles/files/fokemubonafaj.pdfIn PDF document text
    • https://pemaboutiquehotel.com/assets/userfiles/files/24496620651.pdfIn PDF document text
    • http://songdolandmarkcity.com/userfiles/file/47645721047.pdfIn PDF document text
    • http://msslink.ru/userfiles/files/85269883755.pdfIn PDF document text
    • http://alltimescare.com/attachment/files/denupakor.pdfIn PDF document text
    • http://image.dlib.vn/libedu/news/bvu/20210918/file/30121539898.pdfIn PDF document text
    • https://buka.ru/sadm_files/52667092811.pdfIn PDF document text
    • http://fortwashington.abwingsmd.com/uploads/files/65017785661.pdfIn PDF document text
    • http://nsmpublicschool.org/slbdavbatala/userfiles/file/pubisedaduzefizuzuvebi.pdfIn PDF document text
    • http://www.1atlanticfunding.com/wp-content/plugins/formcraft/file-upload/server/content/files/1615312d9c77f6---rapiregukopi.pdfIn PDF document text
    • http://alternativefitness.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16149afd98c2cb---pasixisonabopokivodotarig.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=among+animals+for+example+birds+do+they+lay+eggs+all+through+the+yearPDF 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_off0000d702.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD702 18560 bytes
SHA-256: 8ac9fb304402927178840331af699e27d18e7a73035f0229c68d13188036c6da
font_01_sfnt_off00010758.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10758 11384 bytes
SHA-256: 8e720fff1170d77ddab764e50a3edbdf78075d7f3ade91af1800a1202d8acce2
font_02_sfnt_off0001219a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1219A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1