Malicious PDF — malware analysis report

Static analysis result for SHA-256 d5638cb3ee4a9a93…

MALICIOUS

PDF

81.1 KB Created: 2021-08-26 11:37:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 600fced263db1bb2624a5624b380cf97 SHA-1: 5632b4b038b1ed64279d6aa05dad36fa59bc16f2 SHA-256: d5638cb3ee4a9a93e3dce2483f49f1e5954ace71af7136b5a5cd8bad768d0ad1
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a large number of external links, many of which point to compromised websites or use disposable hosting, indicative of a link farm used for phishing or distributing malware. The ML classifier and ClamAV detection strongly suggest malicious intent. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing content but serving as a vessel for the malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://www.greenlakecruises.com/ckfinder/userfiles/files/supir.pdf In PDF document text
    • http://teplospectr.ru/images/files/bovipasafawi.pdfIn PDF document text
    • https://donnasalon.ru/wp-content/plugins/super-forms/uploads/php/files/637850ee4ce1b25e30b2b1c2fa9c2fa9/84184904541.pdfIn PDF document text
    • https://watertorens.nl/userfiles/file/73816849840.pdfIn PDF document text
    • https://signika.pl/Upload/file/koxegaraxejoxipiboxe.pdfIn PDF document text
    • http://constructionone.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16091e02ec5ef3---43813224227.pdfIn PDF document text
    • http://www.qookspot.kitchen/wp-content/plugins/formcraft/file-upload/server/content/files/160b828b3bd3f0---gunawojegoba.pdfIn PDF document text
    • https://schreinerheusi.de/wp-content/plugins/formcraft/file-upload/server/content/files/16119eb49ddf58---70795811028.pdfIn PDF document text
    • http://webscape.co.bw/wp-content/plugins/formcraft/file-upload/server/content/files/160b9947a048f7---97495721679.pdfIn PDF document text
    • http://ecbpolska.pl/wp-content/plugins/super-forms/uploads/php/files/220783047c476463cb63f106686d343a/xerozivukunufegotizojusu.pdfIn PDF document text
    • http://costanzolegal.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/89923219965.pdfIn PDF document text
    • http://quickvideo.nl/userfiles/file/19703080256.pdfIn PDF document text
    • http://kxqcgs.net/filespath/files/20210820121900.pdfIn PDF document text
    • https://alnahamgroup.com/userfiles/file/54056716561.pdfIn PDF document text
    • http://ipjanah.ir/wp-content/plugins/super-forms/uploads/php/files/513i5ag1gv1mg9j91pej9uv2g0/31709757810.pdfIn PDF document text
    • http://hakkabrothers.com/userfiles/file///8202716238.pdfIn PDF document text
    • https://dursunguney.com/userfiles/files/60760881053.pdfIn PDF document text
    • http://imhyuk.com/imhyukeditor/userfile/file/dotavomuxefak.pdfIn PDF document text
    • http://pocatellocampfire.com/wp-content/plugins/super-forms/uploads/php/files/fqhqcr1ut2cffh02aosb6r80bl/zekubugolijob.pdfIn PDF document text
    • https://goactive.hu/wp-content/plugins/super-forms/uploads/php/files/7bf6849ace2a3f64263a6b4e876cef2c/48517419517.pdfIn PDF document text
    • http://acecaalcoy.com/userfiles/file/nitekowakowodolez.pdfIn PDF document text
    • http://vervesimuhub.com/userfiles/file/49465536151.pdfIn PDF document text
    • https://www.shopveriamici.com/wp-content/plugins/super-forms/uploads/php/files/ta4d108ldtu2f42ggc09vfl6t2/torafilivitaku.pdfIn PDF document text
    • http://kokomo1986.com/clients/31029/File/miwiwe.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/S30rS-6n6vg/uplcv?utm_term=a+question+markPDF 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_off0000dcbe.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDCBE 16328 bytes
SHA-256: 73f7025ade537881a8b2e3f2a83192131407ac33d55bb4e818f61f3e3b3d3f96
font_01_sfnt_off000106f5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x106F5 10540 bytes
SHA-256: 31b065bc38af6bc5632cc62b9edb5e66e70a8c975b8336e9ba3dc1a425f3ad52
font_02_sfnt_off00011f04.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11F04 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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