Malicious PDF — malware analysis report

Static analysis result for SHA-256 50bdec3e1947143b…

MALICIOUS

PDF

72.9 KB Created: 2021-08-30 16:09:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: ff373f2a0904ba7a3fac3f91239387d7 SHA-1: 02c726183a422d78e14a23f546d3e97cabe1d4e0 SHA-256: 50bdec3e1947143b7f3523576d51dce77b3cc440b72df659a2bfac247045f353
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous embedded URLs pointing to external sites, many of which are hosted on compromised CMS platforms or disposable domains, suggesting a phishing or malware distribution scheme. The presence of PDF-specific heuristics like 'PDF_SEO_DISPOSABLE_LINK_FARM' further supports this, indicating the document is structured as a link farm to obscure its true purpose.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://synerhu.ru/uplcv?utm_term=iphone+to+do+list PDF link annotation
    • http://beergolfers.com/blog/images/file/31216144409.pdfIn PDF document text
    • http://artstudiodesign.it/userfiles/files/zenedoxelekuzedudap.pdfIn PDF document text
    • https://www.ezhealthcheck.com/wp-content/plugins/super-forms/uploads/php/files/ai6se4h7up05dd4g6pfup6q34r/6978103499.pdfIn PDF document text
    • https://greenturtleproductions.com.au/wp-content/plugins/super-forms/uploads/php/files/b91dd56ebb9f6a36a47062ea13c26fff/61111289295.pdfIn PDF document text
    • http://brno-skoleniridicu.cz/ckfinder/userfiles/files/dilixoweroxuvulikufoz.pdfIn PDF document text
    • http://nc2e.fr/wp-content/plugins/formcraft/file-upload/server/content/files/160d37cf73ffe5---tunava.pdfIn PDF document text
    • http://www.brennholz-heinlein.de/wp-content/plugins/formcraft/file-upload/server/content/files/1608081ff8671f---xakiz.pdfIn PDF document text
    • https://kitapkaplama.com/upload/ckfinder/files/tufobijotalapi.pdfIn PDF document text
    • http://pck.malopolska.pl/wp-content/plugins/super-forms/uploads/php/files/ff920c13fef64801cc8d7fbc03eade61/1002120770.pdfIn PDF document text
    • http://www.alwaysflorida.com/wp-content/plugins/formcraft/file-upload/server/content/files/161244463442d5---nopotov.pdfIn PDF document text
    • https://circolodelpistone.ch/userfiles/file/fedumud.pdfIn PDF document text
    • http://qbcar.ru/ckfinder/userfiles/files/95882847142.pdfIn PDF document text
    • https://nsck-cykelmotion.dk/userfiles/file/47839700826.pdfIn PDF document text
    • https://mimpishio2bet.com/contents//files/sokex.pdfIn PDF document text
    • http://yakutiaprime.ru/SITE/files/editor/file/kafipigip.pdfIn PDF document text
    • https://arizonapoolcontractor.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ba91eea34df---sidojozusevitixewumun.pdfIn PDF document text
    • https://www.plsok.com/wp-content/plugins/super-forms/uploads/php/files/c48192c3ef832261b61ab0553bd7c269/46282844991.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_off0000bcbd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBCBD 10176 bytes
SHA-256: d336668d3569337c177c5bbe28d5ea5480a7762a1b8aa4db8245cccccbff9315
font_01_sfnt_off0000d364.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD364 16432 bytes
SHA-256: 86b0bbcd400f98903884689fc958d6984c9341fce477f6a8705bb94b8e0741ac
font_02_sfnt_off0000fda1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFDA1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1