Malicious PDF — malware analysis report

Static analysis result for SHA-256 67c843d840352c54…

MALICIOUS

PDF

80.2 KB Created: 2021-09-15 09:36:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 8327f368b4908836479350eae205e2d5 SHA-1: 9a794ee640132bc85f0b23ba3f6190d7f8eb5967 SHA-256: 67c843d840352c549edc205ff5655cd5d29b0be568ef9e22b49505f61606b15d
126 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics, including ClamAV and an ML classifier, indicating malicious intent. It contains a large number of external URIs, many pointing to disposable domains, characteristic of a link farm used to obscure malicious destinations. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://huntic.ru/uplcv?utm_term=evertech+sandbox+mod PDF link annotation
    • http://klwas.org/userfiles/images/file/70300168762.pdfIn PDF document text
    • http://cottoneauto.it/userfiles/files/249007989.pdfIn PDF document text
    • http://refah4ter.info/basefile/hotelrefah4terir/files/36398685187.pdfIn PDF document text
    • http://bachova-terapia.sk/images/file/55441640564.pdfIn PDF document text
    • https://taichielite.com/louis/taichi/ckfinder/userfiles/files/84307177164.pdfIn PDF document text
    • http://www.vivelamusica.es/wp-content/plugins/formcraft/file-upload/server/content/files/16141742b48329---554964175.pdfIn PDF document text
    • https://mimpiindah168.com/contents/files/39990584584.pdfIn PDF document text
    • http://prinsart.ro/uploads/files/sexobenesefovokisiw.pdfIn PDF document text
    • https://epiphanych.com/images/file/86542222370.pdfIn PDF document text
    • https://eledigitalpr.it/allegati/file/38779579930.pdfIn PDF document text
    • http://www.yeosung21.or.kr/ckfinder/userfiles/files/1631282069.pdfIn PDF document text
    • https://estudiowebcolombia.com/ckfinder/userfiles/files/78118928411.pdfIn PDF document text
    • https://funke.be/data/file/687195458.pdfIn PDF document text
    • http://allgeology.ru/ckfinder/userfiles/files/nunolemavonirakabase.pdfIn PDF document text
    • http://ozdoby-betonowe21.pl/Upload/file/79077497587.pdfIn PDF document text
    • http://kriosispl.com/cote_dor_import/admin/ckfinder/userfiles/files/2712354901.pdfIn PDF document text
    • https://simplehome.ro/ckfinder/userfiles/files/44656524909.pdfIn PDF document text
    • http://hightopeducation.com/cms_uploaded/file/wurafetejinapatipo.pdfIn PDF document text
    • https://vetregistr.com/ckfinder/userfiles/files/82448712402.pdfIn PDF document text
    • https://spherule.org/wp-content/plugins/super-forms/uploads/php/files/k7ga8ufspof46pm0itcamikg20/5099694933.pdfIn PDF document text
    • http://qunjl.com/userfiles/files/91240845062.pdfIn PDF document text
    • https://triatlonshop.cz/userfiles/file/jikikej.pdfIn PDF document text
    • https://unchiulmihai.ro/files/fckeditor/file/18331169667.pdfIn PDF document text
    • http://tingchucontrol.com/Uploadfiles/files/sezafodekikaku.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_off0000ca16.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCA16 21628 bytes
SHA-256: 3c0438d0dc3260ec73f49de2fc586355f0f2388e8862885178822ff03737dfdf
font_01_sfnt_off0001027d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1027D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011a94.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11A94 10788 bytes
SHA-256: 30ba3c1d806016afe8bd80211411acd471ab420e3a424c2f3b61c7bddaafeaad