Malicious PDF — malware analysis report

Static analysis result for SHA-256 333835b1fc36ac7f…

MALICIOUS

PDF

73.5 KB Created: 2021-06-24 22:01:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-14
MD5: 0cff426cccf154f0b4b8d48ac4eb67d3 SHA-1: 802b7edc92a298596b8cbe4d90964fc43ee568f6 SHA-256: 333835b1fc36ac7fe7753dec3abfc96c5e685a0432c44c4719772868e953a01d
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The file is identified as malicious by ML classifiers and ClamAV, indicating a phishing or malware distribution attempt. It contains numerous links to external websites, many hosted on compromised WordPress sites, suggesting a link farm designed to redirect users to malicious content. The PDF structure and embedded links are indicative of a spearphishing attachment, likely aiming to exploit user trust.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

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://krisoc.ru/uplcv?utm_term=and+the+sea+will+tell+pdf PDF link annotation
    • http://plusbateria.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b5bce3b63c5---59887876678.pdfIn PDF document text
    • https://www.medipratik.com/wp-content/plugins/formcraft/file-upload/server/content/files/16094bc67dfebe---xudopofimakegofa.pdfIn PDF document text
    • https://hotelritariccione.it/wp-content/plugins/formcraft/file-upload/server/content/files/160b83bb00f061---befisodigik.pdfIn PDF document text
    • http://www.nationaalgolfcongres.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1607da8df4a750---dilefoxuluvizurutula.pdfIn PDF document text
    • https://hotelritariccione.it/wp-content/plugins/formcraft/file-upload/server/content/files/160a5f54bb364a---femugobunuxutezupowuveso.pdfIn PDF document text
    • http://chupanhnoithat.vn/upload/files/junimevumolutatikotup.pdfIn PDF document text
    • https://alihuata.com/userfiles/file/61985029018.pdfIn PDF document text
    • https://heykidsletscook.info/wp-content/plugins/super-forms/uploads/php/files/b249587b6b0fde0b936bea6088b157bc/70099313718.pdfIn PDF document text
    • https://calmoinc.com/upload/editor/file/wisimeluboxirodofejiwuras.pdfIn PDF document text
    • http://gostinica-domodedovo.ru/files/zijezebebovirivup.pdfIn PDF document text
    • https://www.davinci.dk/wp-content/plugins/formcraft/file-upload/server/content/files/1607aed12f3fdb---64628289608.pdfIn PDF document text
    • https://xn--80adj7cxa.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/867a6d64775774593a2f33a6c450ccb0/80013081480.pdfIn PDF document text
    • http://www.altrus.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160745092d3d56---87702776096.pdfIn PDF document text
    • https://teenvolunteerdallas.org/wp-content/plugins/super-forms/uploads/php/files/12cd0f1c7cd84cf54aa89e6c2c915ccd/5559800721.pdfIn PDF document text
    • https://enville.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c6a383f075d---finowakare.pdfIn PDF document text
    • http://antik-cafe-bergen.de/wp-content/plugins/formcraft/file-upload/server/content/files/1607dd2142a353---4780822577.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e5d9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE5D9 5116 bytes
SHA-256: d4980a3ce689a0dc696dccc4fe7a2b6fe6bfb767a6ddbfd08b0a306cf7b395b3
font_01_sfnt_off0000f756.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF756 11512 bytes
SHA-256: 7eedecabfb3cdc10dea971b579885613dc32ee6fbb02ec994f40dd84969dadf4