Malicious PDF — malware analysis report

Static analysis result for SHA-256 3bb990d7efef23d5…

MALICIOUS

PDF

107.6 KB Created: 2021-09-15 14:28:34 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 2629236a1e9f92f32e704330a7c30db1 SHA-1: 1d9f00b50c40b1fe2efd2d0235119eb09fe59060 SHA-256: 3bb990d7efef23d57f9d2465662236cb7f94b980b86eae188d56c1f6ad8c7770
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The sample was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs that form a link farm, with several pointing to compromised CMS upload storage or disposable hosting. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9899

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://299-45.com/CKEdit/upload/files/47543843128.pdf In PDF document text
    • http://www.combatsim.eu/wp-content/plugins/formcraft/file-upload/server/content/files/1613c294a00302---remixulotu.pdfIn PDF document text
    • http://klubalfa.org/img/userfiles/file/3417437206.pdfIn PDF document text
    • http://geyikkimya.com/userfiles/upload/file/19859143139.pdfIn PDF document text
    • http://www.coverseg.com/uploads/ckfinder/files/xapedewek.pdfIn PDF document text
    • https://comptables-publics.fr/userfiles/file/80017193517.pdfIn PDF document text
    • http://detskypohar.cz/upload/file/judujefemidezelaxevowil.pdfIn PDF document text
    • https://kamhosting.nl/ckfinder/userfiles/files/datuvubijapidudo.pdfIn PDF document text
    • http://zkqzl.com/uploadfile/file///2021090115550635.pdfIn PDF document text
    • https://ccskin.com/geektic/files/tewetowo.pdfIn PDF document text
    • http://noxsun.com/jingkelun/userfiles/files/20210910011347.pdfIn PDF document text
    • http://tmkb.org.tr/ckfinder/userfiles/files/29583989055.pdfIn PDF document text
    • https://vhssirimpanam.org/ckfinder/userfiles/files/wubeserodefobemisatelis.pdfIn PDF document text
    • https://rrvchefs.com/wp-content/plugins/super-forms/uploads/php/files/06dece5a2dcbde5638ceffd25ab70750/15864995464.pdfIn PDF document text
    • http://deborahkay.com/ckfinder/userfiles/files/54464596872.pdfIn PDF document text
    • http://www.kevinbrooks.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1612ed449617cf---35265614866.pdfIn PDF document text
    • http://onroerendgoedindex.nl/images/uploads/nufezevojetalekesifejok.pdfIn PDF document text
    • https://www.hungryalex.com/wp-content/plugins/super-forms/uploads/php/files/3d62efceb4368ba5b87d125958af8203/7434248641.pdfIn PDF document text
    • http://rheumatology.institute/upload/content/file/28385722738.pdfIn PDF document text
    • http://tindangnhadat.vn/upload/files/18600805913.pdfIn PDF document text
    • http://stagegator.scorchmark.com/stagegator/ckfinder/userfiles/files/61174052643.pdfIn PDF document text
    • http://abnig.friendship-match.com/upload/files/27024446843.pdfIn PDF document text
    • http://terhautz.com/upload_files/files/ginuf.pdfIn PDF document text
    • https://torgradio.ru/new/files/file/56706141981.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/FevRqgeaUVY/uplcv?utm_term=action+comedy+movies+2020+full+movie+englishPDF 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_off00012545.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12545 11164 bytes
SHA-256: 63e037e1a4fb3b3d2910306c2fd44ebb2261a117c0a4d598bce391700fa6f966
font_01_sfnt_off00013f11.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13F11 20012 bytes
SHA-256: 726a0740ce92e47427293a671c6a214dc8cc8d336d29fcf026ce4a9601781297
font_02_sfnt_off000171fb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x171FB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_03_sfnt_off00018a0c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x18A0C 16164 bytes
SHA-256: a0f26d9ec2bc0bbc84dfb8c1a224a49f7f70479ac92e21d726acd811d43f3bd1

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