Malicious PDF — malware analysis report

Static analysis result for SHA-256 21dce2c3ecf0aceb…

MALICIOUS

PDF

84.1 KB Created: 2021-09-20 14:32:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 728d267340334c18025a2100a015fdce SHA-1: 653ab791147e0e2bb1f37213cb9c2f7c03d05459 SHA-256: 21dce2c3ecf0aceb1841402202f6fcddd897a2a75ce1e840b8afea32621345e4
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and by an ML classifier as malicious. Heuristics indicate it functions as a link farm, with multiple URLs pointing to potentially compromised WordPress uploads and disposable hosting. The document body is heavily obfuscated, preventing analysis of its specific content, but the overall structure and URL analysis strongly suggest a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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 http://tichdiem.surecare.vn/uploads/userfiles/file/66726818194.pdf In PDF document text
    • https://bisleriuber.genefied.co/ckfinder/userfiles/files/56972602956.pdfIn PDF document text
    • https://gkatsov.com/userfiles/file/ximumexitiguzekos.pdfIn PDF document text
    • http://rracc.com/file_media/file_image/file/sajojorokosoluposopeneto.pdfIn PDF document text
    • http://www.pattyn360.com/upload/forum/files/liwajejorijalo.pdfIn PDF document text
    • http://suamanhinhlcd.net/userfiles/file/zepupakiwa.pdfIn PDF document text
    • https://mytekas.com/UserFiles/file/86954381948.pdfIn PDF document text
    • https://kinhdoanhvaphapluat.com/img-dn/files/51683843076.pdfIn PDF document text
    • http://gazdalkodjokosan.hu/img/userfiles/file/54490729638.pdfIn PDF document text
    • https://eurochen.com/UpFiles/WebEditorFiles/file/gatasigevopulini.pdfIn PDF document text
    • http://datacomsystems.cz/userfiles/file/tumosixijoginuvukoxalibe.pdfIn PDF document text
    • http://www.moteco.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1614288a618483---tanimugakuxamapisozawev.pdfIn PDF document text
    • http://ettorebelfioreliutaio.it/userfiles/files/5879765465.pdfIn PDF document text
    • https://kentacademymiango.com/userfiles/file/99521552722.pdfIn PDF document text
    • https://www.ciabrini-immobilier.com/wp-content/plugins/super-forms/uploads/php/files/seq5o21obdf29ruh4aajgl164n/pepuzagoteratoboxesefotej.pdfIn PDF document text
    • http://kystop.com/wp-content/plugins/super-forms/uploads/php/files/3180a6ca3b62336aa07916f3e8d9dc0a/dajusojudodotemojumonir.pdfIn PDF document text
    • http://tysons-cafe.com/uploads/files/29381442866.pdfIn PDF document text
    • https://millinerandassoc.com/files/file/67440956976.pdfIn PDF document text
    • http://x-site.by/upload/editor/files/81664249778.pdfIn PDF document text
    • https://autosofortkauf.ch/wp-content/plugins/super-forms/uploads/php/files/6ciemv5un70p2u8v76dnmouopa/43525941255.pdfIn PDF document text
    • http://xn----7sbakn3aoflleitf3m6a.xn--p1ai/userfiles/file/80488177596.pdfIn PDF document text
    • http://kiuruvedenlukio.fi/tiedostot/file/tewalujekijivexemidomi.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/S30rS-6n6vg/uplcv?utm_term=student+cafe+nudgeePDF link annotation
    • 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_off0000d16d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD16D 16872 bytes
SHA-256: 2adb02dd83b4da4ca0c7fe943cb56344c04182020304905a4435ff9ada398bea
font_01_sfnt_off0000fd21.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFD21 17668 bytes
SHA-256: 8c091192ee027345d2fbc0d9bae8561b1af3f95ed6cc9606d612e6f18f4ee575
font_02_sfnt_off00012ad2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12AD2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1