Malicious PDF — malware analysis report

Static analysis result for SHA-256 a8b819cd8cc78867…

MALICIOUS

PDF

91.6 KB Created: 2021-07-19 21:34:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-15
MD5: 9f7feb8d5929dc9042f9a5251c478a3e SHA-1: 3387fe9a9cb9c3dc38b73c3cd06ce52dc0b7cfe3 SHA-256: a8b819cd8cc7886791604df0baf14744be812bb36cfacdba53b921ed50afab88
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains a link farm pointing to numerous websites, many of which are hosted on compromised CMS platforms. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The document body is heavily obfuscated and unreadable, providing no direct clues to its specific purpose beyond the heuristic findings.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9746

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://allnatureint.com/userfiles/file/jilowezu.pdf In PDF document text
    • http://lapawan15.com/shop/fck_file/file/72283699945.pdfIn PDF document text
    • https://by-express.com/upfiles/editor/files/sajubivokesasudim.pdfIn PDF document text
    • https://stakeoutllc.com/wp-content/plugins/super-forms/uploads/php/files/090fb57fce5f3e40bfe188a1f7dd5e7b/86861488650.pdfIn PDF document text
    • https://rhdplumbing.com/wp-content/plugins/super-forms/uploads/php/files/8b70c2f50caa3381e04a098e5bb5eb0b/nipud.pdfIn PDF document text
    • https://howardsteeves.com/wp-content/plugins/super-forms/uploads/php/files/83072bafcac212aeea012d35c47f1e41/telapog.pdfIn PDF document text
    • http://thefutureofgolf.eu/wp-content/plugins/formcraft/file-upload/server/content/files/1607576d6aabbd---17144917206.pdfIn PDF document text
    • http://aiaato.com/FileData/ckfinder/files/20210701_28C2E0CF95BB2A24.pdfIn PDF document text
    • http://www.brennholz-heinlein.de/wp-content/plugins/formcraft/file-upload/server/content/files/1606c8f3b2b22e---18845167280.pdfIn PDF document text
    • http://bjzjygj.com/fckeditor/editor/filemanager/connectors/php/userfiles/file/jazibevufuvuxokaforopij.pdfIn PDF document text
    • http://business-plan-capalpha.eu/mbp/upload/images/images/upload/ckfinder/fikiliz.pdfIn PDF document text
    • https://oklogistic.lv/upload/file/jofasikufibowabaziwiz.pdfIn PDF document text
    • http://www.ausafrica.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160a2416a50d08---panozolewelakuz.pdfIn PDF document text
    • https://jiptv.nl/wp-content/plugins/super-forms/uploads/php/files/544krla2584up0r9gsd3qouc8o/vajege.pdfIn PDF document text
    • http://visualpaint.com/wp-content/plugins/formcraft/file-upload/server/content/files/16092676c8a138---tejapufumivaja.pdfIn PDF document text
    • http://www.christinemartin.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1607980ed2b4c6---setijesowi.pdfIn PDF document text
    • http://harposwebdesign.nl/app/webroot/files/userfiles/files/3912396569.pdfIn PDF document text
    • https://master.plus/wp-content/plugins/super-forms/uploads/php/files/00d51a5135661bfa2d24798fde966b24/7666749687.pdfIn PDF document text
    • http://yishiweb.com/upfiles/files/20210628_061002.pdfIn PDF document text
    • http://morgancountyoh.com/userimages/vulasusobebutekewefo.pdfIn PDF document text
    • https://www.femregenx.co.za/wp-content/plugins/super-forms/uploads/php/files/44vur2dhj6pj2amkhjdtklclvc/49651796700.pdfIn PDF document text
    • https://www.18fire.com/wp-content/plugins/super-forms/uploads/php/files/20e1709a9ab7f496aeeef7ceed3b7f29/556972827.pdfIn PDF document text
    • http://cainghienbinhduong.com/uploads/userfiles/file/74474265082.pdfIn PDF document text
    • http://ekachaiguitarist.com/ckfinder/userfiles/files/3329974465.pdfIn PDF document text
    • http://seyrimerdin.com/userfiles/file/65840374741.pdfIn PDF document text
    • http://jeugdopdewetenschapsagenda.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160a29bb74097a---74468988651.pdfIn PDF document text
    • https://beaufortbond.com/wp-content/plugins/super-forms/uploads/php/files/12320013ec0793f0dc5710b43ba8a294/nitidorevo.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/FevRqgeaUVY/uplcv?utm_term=dog+addons+for+minecraftPDF 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e0d1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE0D1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f8e3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF8E3 17984 bytes
SHA-256: 237c1f6bcd65b0ef33e183512d2ef91d8054c42ff2abf0dac20cfe62e2ce51b9
font_02_sfnt_off000127dd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x127DD 10776 bytes
SHA-256: 3d0b092db72be43c83a61ff290f3ce8d1418a10b9911c1a0ffb0b10f99be399d
font_03_sfnt_off0001407d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1407D 19232 bytes
SHA-256: e8bbd537766e9057c0723f11a6ac8751f61d883522050aefea7b736f06659794