Malicious PDF — malware analysis report

Static analysis result for SHA-256 0c8caae19bd1af03…

MALICIOUS

PDF

88.2 KB Created: 2021-07-14 00:42:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-13
MD5: b816758c9cb11d0720a9acbe68e24fd3 SHA-1: 2d4e20785e104b7cff77c6ca68ac890ff5ad9eb3 SHA-256: 0c8caae19bd1af0309bdab34ac44afedc8e5ae6e15272f29ebd4072add04ba21
156 Risk Score

Malware Insights

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

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

Machine Learning

  • Nyx PDF Classifier malicious score 0.9952

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://wendi101.com/userfiles/file/simidejebepenusoju.pdf In PDF document text
    • https://arihantgranites.in/wp-content/plugins/super-forms/uploads/php/files/7js5cojus14ecvbfsssde69a74/48750886265.pdfIn PDF document text
    • https://apexforestservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/16071814c205fd---58852956001.pdfIn PDF document text
    • http://www.nandomoraes.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16082bb3001eac---26859857578.pdfIn PDF document text
    • https://beachesbrewing.com/wp-content/plugins/super-forms/uploads/php/files/2c0888f6a67b5b115940cadea4dc5e3c/2286175992.pdfIn PDF document text
    • http://nuyewrecruitment.com/wp-content/plugins/super-forms/uploads/php/files/bd7c917fceeba02a983dde4e9c28ab0d/32700457691.pdfIn PDF document text
    • http://xn--365-pn7mwb654m2qn.com/ckupload/files/21704367064.pdfIn PDF document text
    • https://www.kbstephens.com/wp-content/plugins/super-forms/uploads/php/files/8768bd0c8c498b3083780fd3b60382c4/togesuzapijikine.pdfIn PDF document text
    • http://tplustech.com/images/ckeditor/files/11731277942.pdfIn PDF document text
    • http://www.tecnotrefg.it/wp-content/plugins/formcraft/file-upload/server/content/files/16086dde91dc73---talogaze.pdfIn PDF document text
    • https://asaptransfers.co.uk/wp-content/plugins/super-forms/uploads/php/files/6s2cvft8vesujnnie2n9u9svt5/pixazukojamotu.pdfIn PDF document text
    • https://dangeloremodeling.com/nbloom/fckuploads/file/31518837508.pdfIn PDF document text
    • https://assurancemauricie.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607a5c37ca9bb---dikizatinenep.pdfIn PDF document text
    • http://beergolfers.com/blog/images/file/10149247707.pdfIn PDF document text
    • https://adbadog.com/wp-content/plugins/super-forms/uploads/php/files/dc8bb3a0960b155b47dc41479ecc5fdd/losegimonevutepirebelojo.pdfIn PDF document text
    • http://reclaimsplus.com/wp-content/plugins/super-forms/uploads/php/files/345c42cfcadaf819deda7c432fea47d1/namexirirebakuzed.pdfIn PDF document text
    • https://www.andeanskyline.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607f0f9fc78a4---92977084255.pdfIn PDF document text
    • http://thunderstar.cn/userfiles/file/20210515091435350077973.pdfIn PDF document text
    • https://ladychief.com/wp-content/plugins/super-forms/uploads/php/files/1be4bdeabc644a8cf0d6e6fe591a7d32/36202318102.pdfIn PDF document text
    • http://staropolski.net/Upload/file/28079898355.pdfIn PDF document text
    • https://xn--80aanugxqi.xn--p1ai/admin/ckfinder/userfiles/files/60686490223.pdfIn PDF document text
    • http://tablica-nieruchomosci.pl/uploades/fckeditorfile/lejixodufepew.pdfIn PDF document text
    • http://hgbs.de/userfiles/file/20954070976.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/fzgW7-mxBc0/uplcv?utm_term=what+does+plant+and+equipment+meanPDF 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_off0000f38e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF38E 18064 bytes
SHA-256: 9d5ef4c8a93fc3a7e97dc8f204acc3ff8e5ba40d07cf11600cfc80f25488f4be
font_01_sfnt_off0001230d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1230D 10796 bytes
SHA-256: ee04bd11b4652c9a2bac8dbb96a8025aceddf3cecef8da8833934fad897bee91
font_02_sfnt_off00013b7c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13B7C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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