Malicious PDF — malware analysis report

Static analysis result for SHA-256 c61994729b90221d…

MALICIOUS

PDF

70.6 KB Created: 2021-09-26 13:21:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 26ff9cae8b76580683342a9a1e81aa8a SHA-1: fc021f9e9b8aeaebae22593a7a11aa39d4ca908e SHA-256: c61994729b90221df1256a6e2df54824cabe13b1e1c6b224f87b654062c77793
156 Risk Score

Malware Insights

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

The PDF file contains numerous embedded URLs, many of which point to compromised WordPress sites or disposable hosting, indicating a link farm. The ClamAV detection and ML classifier strongly suggest malicious intent, likely related to phishing or distributing further malware. The primary attack pattern observed is the use of a link farm to redirect users, potentially as part of a spearphishing campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9982

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 http://wmc21.com/ckupload/files/26447194660.pdf In PDF document text
    • http://thunderstar.cn/userfiles/file/20210906205017889678413.pdfIn PDF document text
    • http://artemon.nl/userfiles/file/wozinuj.pdfIn PDF document text
    • http://wx-bm.cn/upload/ckimg/files/202109101556208525.pdfIn PDF document text
    • http://www.deewanalarab.com/up_imgs/vesovanibu.pdfIn PDF document text
    • http://mbfeed.vn/upload/files/bupizupapugitogadozukig.pdfIn PDF document text
    • https://alamansyria.com/userfiles/file/19934193467.pdfIn PDF document text
    • https://newsale.linyn.mobi/upload/ckeditor/pages/files/befivefidu.pdfIn PDF document text
    • http://hzeiger.com/userfiles/file/52050394874.pdfIn PDF document text
    • http://tcihk.com/userfiles/80004377907.pdfIn PDF document text
    • https://www.davidwoodpersonnel.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613ed864e0ee8---50583829256.pdfIn PDF document text
    • https://viboot.traigiongthuha.com/ckfinder/userfiles/files/60998102401.pdfIn PDF document text
    • http://www.nanodrywash.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612ea578c2440---58551863565.pdfIn PDF document text
    • http://pagyesa.org/userfiles/file/20210912204559.pdfIn PDF document text
    • http://madurastones.com/userfiles/file/nularaxofotadugiwo.pdfIn PDF document text
    • http://www.predia.cz/userfiles/file/dopixobifosuwokesojij.pdfIn PDF document text
    • http://remontnoedelo.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1614b3745760a3---38411043155.pdfIn PDF document text
    • http://abwcolley.com/uploads/files/mapefibemetujilupatodozi.pdfIn PDF document text
    • http://siddharpeedam.org/userfiles/file/In PDF document text
    • https://omnistopbollards.com/application/third_party/ckfinder/userfiles/files/70804967805.pdfIn PDF document text
    • http://www.donboscovizag.org/images/files/kiruwopimebikadigukizok.pdfIn PDF document text
    • http://lobanowscy.pl/userfiles/file/76391490163.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BkSY9tpko7c/uplcv?utm_term=planescape+torment+iosPDF 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_off0000b1cc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB1CC 10536 bytes
SHA-256: 8eed7d0d8d204a84c60fba2c747fdc6140b72ec1fde804374a216d4f1da2d540
font_01_sfnt_off0000c9c7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC9C7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000e1d9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE1D9 17488 bytes
SHA-256: 7b2113816b5f9ece62fba199f04b40185d2284418184f7e3ec6fbb8d1107fc07