Malicious PDF — malware analysis report

Static analysis result for SHA-256 3538f1d396f453cb…

MALICIOUS

PDF

81.9 KB Created: 2021-09-15 23:32:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 72c743a76d414c9f05b51d8b24a14455 SHA-1: f7e80428918fc7874ae65c3e5eef4c8e8cecf148 SHA-256: 3538f1d396f453cbaf0bdbd9b404ea2075009f7af4951d4a4c037925239a12b2
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous external links, with heuristics indicating it functions as a link farm on disposable hosting and points to compromised CMS upload storage. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware delivery through these links. No scripts were extracted, and the document body was unreadable.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

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://medvor.ru/uplcv?utm_term=firestick+cleaner+app PDF link annotation
    • http://aurora-c.jp/files/files/41118818604.pdfIn PDF document text
    • https://autoroman-service.ro/imagini_ws/gepukit.pdfIn PDF document text
    • http://heatherjansch.com/ckfinder/userfiles/files/83515280371.pdfIn PDF document text
    • https://mp2020.csysadmin.com/ckfinder/userfiles/files/43812049508.pdfIn PDF document text
    • http://nc2e.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1614219374bdc7---4926971750.pdfIn PDF document text
    • http://apicn.net/upload/files/namolaz.pdfIn PDF document text
    • https://wyslijpaczki.pl/app/webroot/files/userfiles/file/nekizetosutu.pdfIn PDF document text
    • https://maribon.net/app/webroot/files/userfiles/files/70859671535.pdfIn PDF document text
    • http://kopdesign.nl/userfiles/file/57982403555.pdfIn PDF document text
    • https://intekcanada.com/ckfinder/userfiles/files/runitefezub.pdfIn PDF document text
    • http://slxiang.com/v15/Upload/file/202199227505131.pdfIn PDF document text
    • http://limoride.net/gallery/file/29116023575.pdfIn PDF document text
    • http://conservationenergy.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613fbe7d6c5fc---siraralizeg.pdfIn PDF document text
    • https://mayersoffice.com/userfiles/file/46292150513.pdfIn PDF document text
    • https://youxsoft.com/uploads/files/83728502979.pdfIn PDF document text
    • http://ritadas.in/userfiles/file/paxituzol.pdfIn PDF document text
    • https://voolabs.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614090d1ebd1c---fusejadapinami.pdfIn PDF document text
    • http://mofrantech.com/userfiles/file/54976151504.pdfIn PDF document text
    • http://vitanova-cattery.com/upload/file/disefivuvudolujinavizaj.pdfIn PDF document text
    • http://macierz-grodziec.org/files/file/46251464062.pdfIn PDF document text
    • https://colakcivi.com/userfiles/file/44805382860.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_off0000db45.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB45 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f357.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF357 18372 bytes
SHA-256: 220776d25648abda5b36300f5c1490a3724d80ea8f2ecf1174749cffe0b96d22
font_02_sfnt_off000122e3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x122E3 10316 bytes
SHA-256: 0deb36d408ac3c1b197dfa733ee341380eed023787f330ba2ec02cde027e06e6