Malicious PDF — malware analysis report

Static analysis result for SHA-256 f1ba89bffd8af14e…

MALICIOUS

PDF

68.8 KB Created: 2021-09-19 20:38:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: d9281ebe90e5a925955cd83088f08b03 SHA-1: 4534155a4c3f0ac4796b86aed3f7620c6668e680 SHA-256: f1ba89bffd8af14ea8877ae44778215a6d546876cb7816de674f44b11b620917
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was identified as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. Heuristics reveal it functions as a link farm, with numerous URLs pointing to potentially compromised CMS upload directories and disposable hosting. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user consumption but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9849

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 https://kolkatanagariksammelan.org/ckfinder/userfiles/files/lexaleziruxozomokosefox.pdf In PDF document text
    • https://www.unicodesystems.com/wp-content/plugins/super-forms/uploads/php/files/4dnpf39fupsf4bkft5d47imfm7/55141167012.pdfIn PDF document text
    • http://www.cuerpomenteyespiritu.es/wp-content/plugins/formcraft/file-upload/server/content/files/1613de80b9d481---81786205371.pdfIn PDF document text
    • http://gesundheit-im-blog.de/userfiles/file/litujexawugen.pdfIn PDF document text
    • http://odontoflash.eu/userfiles/files/fufedejavixiji.pdfIn PDF document text
    • http://localhomesales.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/161333c521aeae---4050121064.pdfIn PDF document text
    • http://paulbwatkinslaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/gonupejavuviwuku.pdfIn PDF document text
    • http://urbanconstructions.org/images/uploadedimages/file/xuxasejudefag.pdfIn PDF document text
    • http://status.cz/UserFiles/File/xinasatojikoxakevopojomuw.pdfIn PDF document text
    • https://acconpriti.com/ckfinder/userfiles/files/pesozewamejobulevatizetuw.pdfIn PDF document text
    • http://starwindows.ie/ckfinder/userfiles/files/78608569918.pdfIn PDF document text
    • http://nfraccon.org/userfiles/file/fapizafirixu.pdfIn PDF document text
    • https://laughteronlineuniversity.com/images/upload/files/93419051119.pdfIn PDF document text
    • https://lomasdelaweb.com/userfiles/2008.09/file/31512202636.pdfIn PDF document text
    • https://satellietgroep.nl/userfiles/files/gavitonokaf.pdfIn PDF document text
    • http://dongtienlamnghiep.com/upload/file/fonibodevoxosezuwuzu.pdfIn PDF document text
    • http://mclarenquartz.in/ci/userfiles/files/fazamarep.pdfIn PDF document text
    • http://saydersan.com/firma/files/14063579370.pdfIn PDF document text
    • http://gaestehaus-am-erlkoenig.de/img/editor/file/61074945276.pdfIn PDF document text
    • http://reedxtrainternational.com/uploads/pages/file/38736832458.pdfIn PDF document text
    • https://foundationkuzmanov.com/files/34895203500.pdfIn PDF document text
    • https://abcoegypt.com/userfiles/files/62279143044.pdfIn PDF document text
    • http://kachelofen-prommegger.at/7046047461.pdfIn PDF document text
    • http://1544-7419.net/upload/fckeditor/file/46582871850.pdfIn PDF document text
    • https://ystechpro.com/nbloom/fckuploads/file/57828822870.pdfIn PDF document text
    • http://thewellmanteam.com/userfiles/files/vesovepowo.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/fzgW7-mxBc0/uplcv?utm_term=notting+hill+putlockerPDF 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_off0000b105.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB105 14728 bytes
SHA-256: cd4b948d508f6a4ca8927df8b0c6633873da495b0871734d0d3231acbea35f87
font_01_sfnt_off0000d60d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD60D 10492 bytes
SHA-256: cd702f5369091adf3e32e4df2b829da81faf75232ab195a9e7355866124fb82f
font_02_sfnt_off0000eddb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEDDB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1