Malicious PDF — malware analysis report

Static analysis result for SHA-256 81fac273ebdc4680…

MALICIOUS

PDF

78.2 KB Created: 2021-09-07 08:16:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 0061cbfc3d3b04028909087305f781c3 SHA-1: e168799f034dbb0aa1147ac2a164245ff65e582d SHA-256: 81fac273ebdc4680196381f1ebe9afa808603430d3d76b7855832ef4566c5fa3
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains an embedded JavaScript stream and numerous external URIs, many of which are hosted on disposable domains or compromised CMS uploads, indicating a link farm designed to redirect users to malicious content. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 7

  • 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.
  • 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.
  • 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://ketchas.ru/uplcv?utm_term=sketchy+pathology+notes+pdf PDF link annotation
    • http://abwrva.com/uploads/files/44601425854.pdfIn PDF document text
    • http://shyjjc.com/v15/Upload/file/20217292346458048.pdfIn PDF document text
    • http://aaexpansionjoint.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608e712105ba6---72842509446.pdfIn PDF document text
    • http://ntep2008.com/UserFiles/File/46900045052.pdfIn PDF document text
    • http://gptools.net/userfiles/file/7274223783.pdfIn PDF document text
    • http://vitalbafitnessclub.eu/userfiles/files/timokevapibuneranerexix.pdfIn PDF document text
    • http://abovomedia.hu/_user/file/93412276310.pdfIn PDF document text
    • http://goldway.jp/upload/board/file/68385583929.pdfIn PDF document text
    • http://homeopathyhongkong.cn/files/14893154930.pdfIn PDF document text
    • http://mamnonsaokhue.vn/app/webroot/files/ckfinder/files/68300198125.pdfIn PDF document text
    • https://www.andyselfstorage.co.uk/wp-content/plugins/super-forms/uploads/php/files/u30m8jf84b9i3fp3831krhu1ki/kutisan.pdfIn PDF document text
    • http://www.park-seversk.ru/other/js/ckfinder/userfiles/files/waziduwojukumun.pdfIn PDF document text
    • https://nadamasristorante.it/file/14007041301.pdfIn PDF document text
    • https://petrovsky14.ru/docs/files/ruvixuzukijitumokogosuwop.pdfIn PDF document text
    • http://iehyun.com/editorupload/file/jupikesivor.pdfIn PDF document text
    • http://thegioimercedes.com/upload/files/jofopativasomafafonajusak.pdfIn PDF document text
    • https://www.frankcapassoandsons.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608e907d672ef---63292296873.pdfIn PDF document text
    • http://teplo76.ru/uploads/file/51684114469.pdfIn PDF document text
    • https://highlander-inn.com/assets/userfiles/files/84854361245.pdfIn PDF document text
    • http://www.iamgoingto1996.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ac545fb1a39---mekizifusekisovomonedoxe.pdfIn PDF document text
    • http://ildungrice.com/fileupload/fckeditor/file/dudelufuw.pdfIn PDF document text
    • https://gea99.com/ckfinder/userfiles/files/53760410447.pdfIn PDF document text
    • http://superfishinglewood.com/uploads/files/52707814253.pdfIn PDF document text
    • http://for-rent-leuven.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608bafae8a9aa---50988184282.pdfIn PDF document text
    • 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_off0000cb70.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCB70 10988 bytes
SHA-256: aa094099a8c9648a13014f993f4f2ca4823c1caebaad01b1ad2592ba7c573d2a
font_01_sfnt_off0000e4c2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE4C2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000fcd4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFCD4 17928 bytes
SHA-256: dd15f2d3d3a7bea216fe4aded46bf54463a2b03ac8d1c54d70db0434c51945dd

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