Malicious PDF — malware analysis report

Static analysis result for SHA-256 35726ef1b8093f1e…

MALICIOUS

PDF

88.3 KB Created: 2021-10-06 02:31:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 3ba7cafce8b4538cc50719c14610f75d SHA-1: 4fed72580ff3f62dfef3cf890a31d441567fa2d6 SHA-256: 35726ef1b8093f1e9bc2b4726d4d11a895e973ac7d761703eccf0ff378d32457
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a malicious PDF, as indicated by ClamAV and ML detection. It contains numerous external URLs, suggesting it functions as a link farm or phishing lure. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this, noting a high number of distinct hosts and UTM parameters, typical of SEO poisoning or spam campaigns. No scripts were extracted, but the embedded URLs are the primary indicators of malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9982

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://inwebjor.ru/uplcv?utm_term=southern+accent+pronunciation PDF link annotation
    • http://zoltysnieg.pl/pliki_wyswig/files/4308597784.pdfIn PDF document text
    • https://dispomydeal.com/wp-content/plugins/super-forms/uploads/php/files/baff86c77d505a9522cb05b81f6435c0/67609873233.pdfIn PDF document text
    • http://tkhomedeco.com/assets/uploads/ckedit/files/20210904073018.pdfIn PDF document text
    • http://0228339500.kad.tw/kads/ckfinder/userfiles/files/60198518153.pdfIn PDF document text
    • https://www.grandeprairie.org/wp-content/plugins/formcraft/file-upload/server/content/files/1615cd6096b9c3---25863502227.pdfIn PDF document text
    • https://hostsolutions.ro/app/webroot/files/userfiles/files/suruliwugovewo.pdfIn PDF document text
    • http://jujucuisine.com/userfiles/file/39805783195.pdfIn PDF document text
    • http://feriaalainversa.com/uploaded/files/gazotovinukufinogubojif.pdfIn PDF document text
    • https://littleitalypizzany.com/nbloom/fckuploads/file/94349224896.pdfIn PDF document text
    • http://bjhtdszdh.com/v15/Upload/file/2021926183535111.pdfIn PDF document text
    • http://tuzy.pl/Upload/file/zewigobadikijuzinosaguzo.pdfIn PDF document text
    • http://futboltotal.net/images/files/pizokolologinoluvajetira.pdfIn PDF document text
    • http://aqcorth.specialty-match.com/upload/files/vewifujisetomezu.pdfIn PDF document text
    • http://pegastelco.com/pictures/files/sutobopikexejosibe.pdfIn PDF document text
    • http://sp2wronki.pl/fotki/fotki/file/gorovul.pdfIn PDF document text
    • http://idevoz.rs/files/wozefodebujofava.pdfIn PDF document text
    • http://aftckwt.com/uploads/file/tekudokuke.pdfIn PDF document text
    • https://ispartaprefabrik.com/ckfinder/upload/files/48742689175.pdfIn PDF document text
    • http://architettipassarinmarzotto.com/userfiles/files/79900358500.pdfIn PDF document text
    • http://nakajima-ya.com/upload/save_image/files/35441555909.pdfIn PDF document text
    • https://machnik.net/ckfinder/userfiles/files/wobulunonimuzafi.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_off0000f439.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF439 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010c50.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C50 10432 bytes
SHA-256: 334da9520ad626ce82b85f354b195b17d5de901403aaebdb99addea3460b1070
font_02_sfnt_off000123ea.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x123EA 18584 bytes
SHA-256: 9cf3848d4a58b66cac7e23da7bafa91c3192e8a8fe63c91dd290e04610b85bb2

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