Malicious PDF — malware analysis report

Static analysis result for SHA-256 a1d6ae05c0ee7ed0…

MALICIOUS

PDF

84.7 KB Created: 2021-08-17 23:29:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 03c1facfa9c61423b05920cdaac03a90 SHA-1: 1e51dd61b8673b8629d7489b306353439ccd58ad SHA-256: a1d6ae05c0ee7ed06e7dae93265ccc1655247f574ef86af5f210b33ae7f3240e
112 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript and numerous links to external PDFs hosted on compromised websites, suggesting it's part of a link farm designed to distribute malware. The ML classifier strongly flagged this PDF as malicious. The embedded JavaScript likely facilitates the download and execution of a second-stage payload from one of the linked URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://cristiandellavedova.com/wp-content/plugins/super-forms/uploads/php/files/4o85o2g20421b0m9oc17t9dja6/duxipenuxuzavofot.pdf
    • http://www.asap-recruitment.net/upload/file/palufexozeko.pdf
    • http://vuonlan.vn/data/upload/files/9871343001.pdf
    • http://gamjagolla.com/uploads/files/99496746979.pdf
    • http://www.sg-callenberg.de/wp-content/plugins/formcraft/file-upload/server/content/files/16090b763ef51e---wojobewaxakulajew.pdf
    • http://vibrosystem.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160784edab1c01---55925227933.pdf
    • https://escaletravel.com/userfiles/files/19450133593.pdf
    • http://kasaitogo.com/uploads/files/18319844239.pdf
    • https://www.kiakaha.gr/wp-content/plugins/super-forms/uploads/php/files/8lnqp9omojekhpqlmajohpf6mo/39500582908.pdf
    • http://libertyquad72.fr/userfiles/file/9029219747.pdf
    • http://auksozvynas.lt/userfiles/file/jawipejazinadatipotarixev.pdf
    • https://backcountryplayground.com/wp-content/plugins/super-forms/uploads/php/files/34bf66fa5c732c6118d44a6dfd1ca76f/nogatowubozubafo.pdf
    • http://plovdivweek.com/app/templates/js/ckfinder/userfiles/files/19542590774.pdf
    • http://fabtur.ru/upload/files/25632201795.pdf
    • http://519pf.com/userfiles/files/kexibipajonuje.pdf
    • http://www.medicalalliedtraining.com/wp-content/plugins/formcraft/file-upload/server/content/files/160852e7699802---kumenobovarepovopuj.pdf
    • https://www.numberoneporthill.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16076c0982273d---kolibegenadivomolovazo.pdf
    • http://for-rent-antwerp.com/wp-content/plugins/formcraft/file-upload/server/content/files/16073d21b55895---69575016.pdf
    • https://rescue.bg/wp-content/plugins/formcraft/file-upload/server/content/files/160d82eaed97e3---94988650281.pdf
    • https://kiaavcilar.com/upload/ckfinder/files/56353040032.pdf
    • http://open.ua/uploads/ckeditor/files/mufolakufafidupafis.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/PmAiG5ZyT-k/uplcv?utm_term=angry+birds+star+wars+2+old+version+apk
    • 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_off0000e31a.bin
359a9c4d9d0a3b30811a6cb20da62760e30f563dcde9bb0d4ee325c0347b90ee
pdf-font-stream PDF embedded font (sfnt) at offset 0xE31A 18676 bytes
font_01_sfnt_off000111e1.bin
aad6ddaf53fe230a15f1485eeab0ff90c502a9acdb1c412490e2c1038b264081
pdf-font-stream PDF embedded font (sfnt) at offset 0x111E1 11164 bytes
font_02_sfnt_off00012bd8.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x12BD8 16792 bytes