Malicious PDF — malware analysis report

Static analysis result for SHA-256 03357556539eb6f3…

MALICIOUS

PDF

80.6 KB Created: 2021-09-03 13:09:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 270571b59877c17752d4a6af557047ba SHA-1: 530311782c244240a5113484bab034dc0cba14bc SHA-256: 03357556539eb6f3890e650425a5f6e4f2e47a726bb8af89329f3057044f375f
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is a PDF containing numerous embedded URLs, many of which point to compromised WordPress sites or disposable hosting, indicating a link farm designed to distribute malicious content or phish users. The ClamAV detection and ML classifier strongly suggest malicious intent, likely related to phishing or malware delivery via these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

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=baxi+system+boiler+35%2F80+ie+manual PDF link annotation
    • http://rheumatology.institute/upload/content/file/34557298479.pdfIn PDF document text
    • https://dintek.eu/uploads/file/moxozirozamad.pdfIn PDF document text
    • https://www.bluegreenshouseboats.in/wp-content/plugins/formcraft/file-upload/server/content/files/160776794b1231---37834698558.pdfIn PDF document text
    • https://trsbarriersdirect.com/wp-content/plugins/super-forms/uploads/php/files/rt2b9aaqni3dku2nenl5omct3s/zuxobojakiw.pdfIn PDF document text
    • http://laclonghotel.vn/upload/files/39084917836.pdfIn PDF document text
    • http://mrukseo.pl/userfiles/file/73220190489.pdfIn PDF document text
    • http://spoanalyze.com/wp-content/plugins/super-forms/uploads/php/files/db6180216f74ae55827ac4aec9ac3190/35796362451.pdfIn PDF document text
    • http://toanthinh.vn/webroot/img/files/14420569097.pdfIn PDF document text
    • https://vientangluc.com/upload/files/78368782506.pdfIn PDF document text
    • http://fine-cottage.ru/userfiles/files/faxekedekudewatumaxenax.pdfIn PDF document text
    • https://shining4u.com/wp-content/plugins/super-forms/uploads/php/files/a4bf34e2d67e787bc450ac4ad43a771e/remoxup.pdfIn PDF document text
    • https://dacoma.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1609ce5a31deb6---25375454891.pdfIn PDF document text
    • https://pindimana.in/uploads/file/71400856981.pdfIn PDF document text
    • http://tsradviseurs.nl/mailing/images/photo/file/kunowole.pdfIn PDF document text
    • http://mazurubezpieczenia.pl/zdjecia/fck/file/kajowufor.pdfIn PDF document text
    • http://ihdbd.org/upload/files/fiserekufasuserame.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_off0000d398.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD398 17952 bytes
SHA-256: 992f6fa9f6f00425a134456ec9ca2076e3e53a603077eccbeac578723d98be65
font_01_sfnt_off00010265.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10265 11448 bytes
SHA-256: 154ce22bdb57eaf584c1a2a4c911d1bc8b4946c8e9da4e6f321a1adcdb538248
font_02_sfnt_off00011d97.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11D97 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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