Malicious PDF — malware analysis report

Static analysis result for SHA-256 4b11828be52cbf52…

MALICIOUS

PDF

86.2 KB Created: 2021-07-24 01:15:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 11e294eb1c76c0b448df24d911cad7b4 SHA-1: 75b145ef883715505f92cccf842ce896bfe60c78 SHA-256: 4b11828be52cbf52df56028aa9689ebc32bd0d1a9ecbc99212ad23bf43400b2c
156 Risk Score

Malware Insights

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

The PDF was flagged by a machine learning classifier and ClamAV as malicious, indicating a high likelihood of malicious intent. It functions as a link farm, with many URLs pointing to compromised WordPress uploads and disposable hosting, suggesting an attempt to distribute phishing content or malware. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://lezeckastenakosice.sk/upload/files/6617290251.pdf In PDF document text
    • http://wrtour.com/FileData/ckfinder/files/20210625_2F489C58F6FA8C8F.pdfIn PDF document text
    • https://aldea.work/wp-content/plugins/super-forms/uploads/php/files/e45deadcbf41fbe4f6d6fd6840254741/70589081199.pdfIn PDF document text
    • http://julieesteban.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b8ce65e46c1---tunuwurosiket.pdfIn PDF document text
    • http://www.rec39.ru/wp-content/plugins/super-forms/uploads/php/files/eeb2d8432e700e9c1cfb5d135fd8c9a9/69995840956.pdfIn PDF document text
    • http://movementlab.dk/userfiles/file/rezufamolelapu.pdfIn PDF document text
    • http://kowel.com/ckfinder/userfiles/files/1626692028.pdfIn PDF document text
    • https://endoaccessories.com/wp-content/plugins/super-forms/uploads/php/files/ougs6iaj1i8j6loqonr3n2d8l2/nesenevosenakevan.pdfIn PDF document text
    • https://rebel-guitars.com/wp-content/plugins/super-forms/uploads/php/files/7e7a10c24db6ba90391fdb0f7adf08de/banununujaw.pdfIn PDF document text
    • http://lavalnerina.it/userfiles/file/kujobilesejemiled.pdfIn PDF document text
    • https://sarujiovalente.com/wp-content/plugins/super-forms/uploads/php/files/fbe8vul0h15op9q8no3mctqgl6/zipiridal.pdfIn PDF document text
    • https://www.acetechnology.co.in/wp-content/plugins/super-forms/uploads/php/files/1dd8a2cforjcd599q2kuko3qp3/46563633843.pdfIn PDF document text
    • https://baxsporthorses.com/userfiles/file/belobubadatelufit.pdfIn PDF document text
    • http://provia-events.de/pics/fotos/1/file/78213769232.pdfIn PDF document text
    • http://www.asejnrtigers.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16084cefa52a1a---54517673409.pdfIn PDF document text
    • https://extremetour74.ru/wp-content/plugins/super-forms/uploads/php/files/08715f2864b86cc9b3975152b1b57352/66750305871.pdfIn PDF document text
    • https://binhvi.com/upload/files/kalimuwederiridapupude.pdfIn PDF document text
    • http://sdes.in/uploads/99800518085.pdfIn PDF document text
    • https://rmissio.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1608ac968441c9---fejorovodalukotebagofiruz.pdfIn PDF document text
    • http://www.empresasdelimpeza.info/wp-content/plugins/formcraft/file-upload/server/content/files/1607de3434ce3c---lazolenazulosisul.pdfIn PDF document text
    • http://hyosangjo.com/userfiles/file/20210720153403.pdfIn PDF document text
    • http://art-lan.ru/uploads/assets/file/zikefewukekosunejeka.pdfIn PDF document text
    • http://www.elsecretodelolivo.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c055d6117f1---kixut.pdfIn PDF document text
    • http://bizwd.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a06dd6c689a---tagaseselizebelanes.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/1KS0DP0cxss/uplcv?utm_term=how+to+reset+pelonis+space+heaterPDF 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_off0000edb5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEDB5 17204 bytes
SHA-256: e21275051c2181abc4a12fce64f5c93a7330b876f547043be24ff75930813f42
font_01_sfnt_off00011b15.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11B15 10548 bytes
SHA-256: d54474549d55b4e2fd5aaf43708f688d31047dd90c50c37d5fbdbd07260b024e
font_02_sfnt_off0001331a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1331A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1