Malicious PDF — malware analysis report

Static analysis result for SHA-256 35c37f409691619f…

MALICIOUS

PDF

126.3 KB Created: 2021-09-02 19:14:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 0b3cc742e1008edec305d20d3ec6d794 SHA-1: 3db8d35e1d4d62558589c7c6cfa6500f736aadc2 SHA-256: 35c37f409691619f2f9a7ff6f9deff2c4ca6bd4f70033c23dd3174d00e335f76
156 Risk Score

Malware Insights

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

The PDF contains a large number of links, many pointing to compromised WordPress sites, suggesting a link farm designed to distribute malicious content or phish users. The ClamAV detection and ML classifier further support its malicious nature. No scripts were extracted, and the document body was unreadable, so the primary attack vector is the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.6571

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
  • PDF differential parser failed info PDF_DIFFERENTIAL_PARSE_FAILED
    The cross-check parser (pdfminer.six) failed on this file: PDF differential parser failed: PDFSyntaxError. Static heuristics still ran and any of their findings above are valid; only the differential cross-check signal is missing.
  • 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 http://humboldthighclassof79.com/clients/1/19/19f040aad945c40a0acbd79abd3dc6cb/File/febodazo.pdf In PDF document text
    • https://www.hdcorp.com.br/wp-content/plugins/super-forms/uploads/php/files/q41r9ldnbk1jk761vbqsd4ccv4/8297559502.pdfIn PDF document text
    • https://novamakine.com/upload/ckfinder/files/xinidikisemo.pdfIn PDF document text
    • http://www.brennholz-heinlein.de/wp-content/plugins/formcraft/file-upload/server/content/files/160bb5518600ac---52976802615.pdfIn PDF document text
    • http://tostonet.cl/ckfinder/userfiles/files/bigukedarafuzuxuvexa.pdfIn PDF document text
    • http://vasilii-orlov.fun/wp-content/plugins/super-forms/uploads/php/files/e80b2caefcd61ffe6b214fd5db9d8ba4/pikorafaturumupeworum.pdfIn PDF document text
    • https://www.brunosistemi.com/wp-content/plugins/formcraft/file-upload/server/content/files/160acf8f58c02e---pisivokuzataxive.pdfIn PDF document text
    • http://enricobarraco.com/files/lovabewebi.pdfIn PDF document text
    • http://asu.com.vn/wp-content/plugins/super-forms/uploads/php/files/6cip4apur222jg8tr1qdsv84ds/29010647723.pdfIn PDF document text
    • http://starrsgazette.com/admin/images/file/lowigalipedetuf.pdfIn PDF document text
    • http://www.kissdocs.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160a0d7566190f---puzar.pdfIn PDF document text
    • https://www.siemers-deutschmann.de/wp-content/plugins/super-forms/uploads/php/files/la1qr0sadfmrbva38vbdo9je01/zepewizaw.pdfIn PDF document text
    • https://sharzh-ufa.ru/wp-content/plugins/super-forms/uploads/php/files/3b336183ef5505898e8dfb9b34b86f75/xupumenom.pdfIn PDF document text
    • https://jgmurphy.com/wp-content/plugins/super-forms/uploads/php/files/13b52d63a6fd07eea568836cfe8544d4/zusoxom.pdfIn PDF document text
    • https://rlvanstory.com/wp-content/plugins/super-forms/uploads/php/files/f39f221c178ed3422e275c31211546ee/4181239050.pdfIn PDF document text
    • http://www.mezmat.ru/ckfinder/userfiles/files/tesuxusa.pdfIn PDF document text
    • https://neoville.ru/wp-content/plugins/super-forms/uploads/php/files/dcc852db96cd8f0cfccd99c35afa71a8/fetebidad.pdfIn PDF document text
    • http://unipell.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160beadfe876e0---24899575649.pdfIn PDF document text
    • http://aven.su/userfiles/file/57040330491.pdfIn PDF document text
    • https://searchlink.org/userfiles//file/leguxijuxuvimur.pdfIn PDF document text
    • http://hertzlaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/legizon.pdfIn PDF document text
    • http://karthikeyanjayaram.com/userfiles/file/vanafazamufinudebufur.pdfIn PDF document text
    • http://minuspk.ru/minuspk.ru/userfiles/file/vulasuvadifabi.pdfIn PDF document text
    • https://amenagementsoleil.com/wp-content/plugins/formcraft/file-upload/server/content/files/16094ed0914699---25047946365.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1KS0DP0cxss/uplcv?utm_term=2004+cadillac+escalade+ext+manualPDF link annotation
    • 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_off00018de4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x18DE4 10736 bytes
SHA-256: 88ec46348125d7ae1d23c9c73ee47b4f15947eb14fdb7c1b7a3b8ac47c2dc513
font_01_sfnt_off0001a6a9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1A6A9 20984 bytes
SHA-256: d022770ad76cdd0b3ff3cc65b99994b491acc29ac7b39666797b92674e47f7cb
font_02_sfnt_off0001dd7b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1DD7B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1