Malicious PDF — malware analysis report

Static analysis result for SHA-256 4c3d507358e6e689…

MALICIOUS

PDF

71.3 KB Created: 2021-09-25 16:28:51 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-21
MD5: d41e75c870408d0b9ad05f5dbc47570a SHA-1: adce48cfc8eb14b6c50b2219b884e4c73f8e2e22 SHA-256: 4c3d507358e6e689d01be2b333780b6f183df9a74350dada314b36a83d4521c3
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as malicious by ClamAV and an ML classifier, and contains embedded JavaScript. It also features a link farm pointing to compromised CMS uploads and disposable hosting, with one URL specifically mentioning 'pdf to xlsx converter online', suggesting a lure for users seeking document conversion tools. The presence of JavaScript indicates potential for further malicious actions, such as downloading additional payloads or redirecting users to phishing sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://inwebjor.ru/uplcv?utm_term=pdf+to+xlsx+converter+online PDF link annotation
    • http://pes.edu.mn/ckfinder/userfiles/files/legapezuridegu.pdfIn PDF document text
    • http://dgjinhak.kr/DATA/upload/files/202109210823145708.pdfIn PDF document text
    • https://sabagdasarov.ru/upload/file/93123381944.pdfIn PDF document text
    • https://www.diktu.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614d182ae6133---58000272358.pdfIn PDF document text
    • http://cobweb.janci.net/upload/files/95385992383.pdfIn PDF document text
    • http://sobinco.cz/ckfinder/userfiles/files/vesisepu.pdfIn PDF document text
    • http://skupka54.ru/upload/m/noredexezekijokotepal.pdfIn PDF document text
    • https://vakukh.ru/wp-content/plugins/super-forms/uploads/php/files/397632f0d07ddc985db83b33ba51cfee/5199792427.pdfIn PDF document text
    • https://autosaloncenter.com/uploads/files/tepumobafajewixev.pdfIn PDF document text
    • http://www.phsdcenter.com/temp/js/ckfinder/userfiles/files/warivanakakojek.pdfIn PDF document text
    • http://arabstina.com/ckfinder/userfiles/files/54711282170.pdfIn PDF document text
    • http://placc.info/up_image/sewuxafojifuniletifo.pdfIn PDF document text
    • http://circolonauticofavignana.it/userfiles/files/68394437389.pdfIn PDF document text
    • http://eternaseguros.net/files/files/tiwowiwiwup.pdfIn PDF document text
    • https://fultoys.com/userfiles/76100909139.pdfIn PDF document text
    • http://everest-c.ru/ckfinder/userfiles/files/fivavovijujarekifedazeg.pdfIn PDF document text
    • http://bielwod.com/userfiles/file/ruwukanif.pdfIn PDF document text
    • https://coaching-jk-academic.com/ckfinder/userfiles/files/lurozuvabevowulav.pdfIn PDF document text
    • https://ebus.myskoolapp.com/FCKeditor/FCKimgUpload/file/femowovosoxulijapotona.pdfIn PDF document text
    • https://designmaster.in/scgtest/eec-new/codelibrary/ckeditor/ckfinder/userfiles/files/texubukodinebexejovawap.pdfIn PDF document text
    • https://pabausa.org/wp-content/plugins/formcraft/file-upload/server/content/files/1614c413dd4838---20017029726.pdfIn PDF document text
    • http://chanhungcorp.com/images/uploads/files/noduvaxesifavowutide.pdfIn PDF document text
    • http://furkansigorta.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/1613576001ff58---78248532212.pdfIn PDF document text
    • http://bkht.vn/userfiles/file/wutesujiduzolevelimir.pdfIn PDF document text
    • http://refah4ter.info/basefile/hotelrefah4terir/files/15874934680.pdfIn PDF document text
    • 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_off0000b53f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB53F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cd51.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCD51 16336 bytes
SHA-256: 6e67a562ecadbf59f687eec89b29c4b03e65ea221a44aa72fbca87d2aee766f9
font_02_sfnt_off0000f77f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF77F 10476 bytes
SHA-256: 77fceb845a5bd6b8ce2b68687340e21cd218b3a28f08302cabbfcfdbbcdedf35