Malicious PDF — malware analysis report

Static analysis result for SHA-256 cb4a81987ce7f045…

MALICIOUS

PDF

79.8 KB Created: 2021-09-16 13:16:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 8f5dd50d102bdb177a2a12ec05c7485d SHA-1: 8cbcd21ec57a296812d9016fa849b4221761dd18 SHA-256: cb4a81987ce7f045105e502abc0ef76022f92d21a68227a2aed7bbc53fbf0999
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was identified as malicious by ML classifiers and ClamAV, specifically flagged as a phishing trojan. It contains numerous embedded URLs, many of which are part of a link farm hosted on disposable domains, suggesting an attempt to distribute malicious content or phish users. The `PDF_SEO_DISPOSABLE_LINK_FARM` heuristic further supports this, indicating a tactic to obscure the true malicious destination.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9968

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://nomylo.ru/uplcv?utm_term=how+to+transfer+ringtones+from+one+android+phone+to+another PDF link annotation
    • http://matsonconstruction.net/userfiles/file/livubetererun.pdfIn PDF document text
    • http://www.blackhillsdancecentre.com/wp-content/plugins/formcraft/file-upload/server/content/files/16131e23906c9a---22647870688.pdfIn PDF document text
    • https://ms1oke.com/contents/files/21784055412.pdfIn PDF document text
    • http://webursitet.org/Files/file/semafekefifejoj.pdfIn PDF document text
    • http://wx-test.com/upload/ckimg/files/202109081647547623.pdfIn PDF document text
    • https://unitedcardsolutions.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613534a22d7da---76160443862.pdfIn PDF document text
    • https://gamma-electronics-eg.com/userfiles/files/87911766606.pdfIn PDF document text
    • https://baglab.pl/galeria/file/546351329.pdfIn PDF document text
    • http://marktoby.com/akram/know_news/admin/userfiles/file/98027835141.pdfIn PDF document text
    • https://bem-sa.com/img/file/87760047897.pdfIn PDF document text
    • http://www.ez4parcel.net/upfile/files/2021/09/06/zokodanijabefibalujop.pdfIn PDF document text
    • https://cvssteelex.com/ckfinder/userfiles/files/2985760637.pdfIn PDF document text
    • http://nexxosrealty.com/userfiles/files/7923708985.pdfIn PDF document text
    • http://hc6999.com/userfiles/files/16920831071.pdfIn PDF document text
    • https://viceda.com/userfiles/file/37099358390.pdfIn PDF document text
    • http://hit-air.pro/ckfinder/userfiles/files/pimenesototepugete.pdfIn PDF document text
    • http://justsayhi365.com/uploads/file/57675950385.pdfIn PDF document text
    • https://guruamardaspublicschool.com/userfiles/files/boneluxutarewogej.pdfIn PDF document text
    • http://nwatchonline.org/userfiles/file/bofuvup.pdfIn PDF document text
    • http://de.ruben.pl/ckfinder/userfiles/files/47179303772.pdfIn PDF document text
    • http://lanaecoloridabruzzo.it/userfiles/file/segoxilubolidi.pdfIn PDF document text
    • http://e-skala.pl/userfiles/file/94139819937.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_off0000cf22.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCF22 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e739.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE739 10976 bytes
SHA-256: d2385b19135cd30e1e4a203895bc913046192b99b8f4aac73d445a33f51cc71a
font_02_sfnt_off00010054.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10054 19132 bytes
SHA-256: 1487849122c435cf824bb4029b93c21f735af4dcfd6d2ed78bbda6a8e929cea8

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