Malicious PDF — malware analysis report

Static analysis result for SHA-256 21bc90fd6a7710cc…

MALICIOUS

PDF

71.0 KB Created: 2021-09-27 21:08:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 275609cba19a8a8fd957e14c85d5e327 SHA-1: 8a2cbac31daf4f067885090ee0ad111da0d10999 SHA-256: 21bc90fd6a7710cca93118b607e503703c91270dcf1fa1b88f4230be7fe03c99
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. The presence of numerous external URIs, many pointing to link farms, suggests an attempt to redirect users to malicious sites. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this, indicating a tactic to obscure the true destination. No scripts were extracted, but the overall structure and heuristics point towards a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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 http://outspokenholland.com/userfiles/fckFile/20210918233312.pdf
    • http://sreema.org/FCKeditor/file/82517741824.pdf
    • http://jinistudy.com/_UploadFile/Images/file/60315434896.pdf
    • http://seoulmenu.com/uploads/files/71799845434.pdf
    • http://drapa-technika.cz/UserFiles/File/kikuzivaxewezowotimutupav.pdf
    • http://khocabien.com/uploads/files/zukonadejedafoxapejomadef.pdf
    • http://asu.com.vn/wp-content/plugins/super-forms/uploads/php/files/shaipu321atf5eq5em8a940qua/8055652268.pdf
    • http://samuiluxurytravel.com/Uploads/file/voxaradutulutemetopixilox.pdf
    • http://zzlhlt.com/userfiles/file/LianMeng202109231907111923.pdf
    • http://cesurmakina.com/userfiles/file/kesotirupomaj.pdf
    • https://vas-vill.hu/userfiles/file/93309482754.pdf
    • http://smeeing.com/userfiles/files/36687579847.pdf
    • http://gvs-russia.ru/admin/ckfinder/userfiles/files/2134763921.pdf
    • https://cutletsmeat.com/wp-content/plugins/formcraft/file-upload/server/content/files/16137eb93812f8---gozosufisoterelutumuv.pdf
    • http://limobebe.com/userfiles/files/gimusigelilosudu.pdf
    • https://lotte-ppta.net/beta/assets/file/63285740084.pdf
    • http://poliinc.com/upload/files/91671177295.pdf
    • https://vibingvibes.com/userfiles/files/81255488877.pdf
    • https://genegurumiraclehealer.com/userfiles/file/vubekenafef.pdf
    • http://cisseo.net/userfiles/files/tajurubilowujise.pdf
    • http://redskap.ru/userfiles/file/pifeva.pdf
    • http://phukientubepxinh.info/gomsu/sanpham/anh/files/58747227160.pdf
    • http://www.jindatunnel.com/up_files/file/16736255299.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/PmAiG5ZyT-k/uplcv?utm_term=french+to+english+translator+android+app
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000b04b.bin
fecafb7e9f5c80d2f1eebab11fd3e2a35f0159fc37fb05e3c4a50dade728db08		 pdf-font-stream PDF embedded font (sfnt) at offset 0xB04B 17196 bytes
font_01_sfnt_off0000dc0c.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0xDC0C 16792 bytes
font_02_sfnt_off0000f423.bin
38842f09d94350a837d48c91beff1f0dfbec6a6f7e6ace8429ab43b7aeac7584		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF423 10768 bytes

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