Malicious PDF — malware analysis report

Static analysis result for SHA-256 7a9c99bd604918d2…

MALICIOUS

PDF

77.8 KB Created: 2021-07-15 23:32:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: c6bb886efb05057553e1d138a955698c SHA-1: 6175f336c26a7ffdb1175516616556aa1c3570d0 SHA-256: 7a9c99bd604918d264359b8ff8adf37317b6878ff41fa728c1e8cadf523c2db2
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a large number of embedded URLs, many of which point to PDF files hosted on various domains. Several heuristics indicate this is a link farm, with some links pointing to compromised WordPress upload storage. The ML classifier strongly flagged this PDF as malicious, suggesting it's part of a campaign to distribute malicious content or manipulate search engine results. No scripts were extracted, but the structure and URL patterns are indicative of a malicious distribution or SEO poisoning attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9963

Heuristics 5

  • 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 http://cestovni-postylka.eu/userfiles/file/98541219228.pdf In PDF document text
    • https://daaeportrett.no/upload/file/ragorefofojo.pdfIn PDF document text
    • http://clubselectionvoyages.com/images/file/73249109344.pdfIn PDF document text
    • https://creteotels.gr/FCKeditor/userimages/file/91620018803.pdfIn PDF document text
    • https://alamansyria.com/userfiles/file/6084792777.pdfIn PDF document text
    • http://www.uppld.org/wp-content/plugins/formcraft/file-upload/server/content/files/160beefe6682df---kemimiba.pdfIn PDF document text
    • http://utuin.net/files/fckeditor/file/vezupovamod.pdfIn PDF document text
    • https://chamsocmuihong.com/wp-content/plugins/super-forms/uploads/php/files/p646ajjtbd1kh9hfh73723j9m9/mizusimiwivekepovi.pdfIn PDF document text
    • http://gocchame.vn/app/webroot/img/uploads/files/nufinulur.pdfIn PDF document text
    • http://xn--80aagkbrca3apkgkee0a1bi.xn--p1ai/ckfinder/userfiles/files/dazakevev.pdfIn PDF document text
    • http://theonejsc.com/userfiles/file/66748493943.pdfIn PDF document text
    • http://www.telsercom.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608f5d1604484---ratanexapaj.pdfIn PDF document text
    • http://www.viksexteriors.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d466ae8b525---zedigarabojuluvuguxo.pdfIn PDF document text
    • https://juraganmonyet.com/contents//files/kojotavujinapome.pdfIn PDF document text
    • https://darshanam.com/ckfinder/userfiles/files/89125907329.pdfIn PDF document text
    • http://dabien.co.kr/wp-content/plugins/formcraft/file-upload/server/content/files/1607da69932781---gomogan.pdfIn PDF document text
    • http://fincasotilloviejo.es/files/sotillo/_repo/file/37458929649.pdfIn PDF document text
    • https://xn----9sbccjdbca7cyaieg1a3j.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/d6c05426227f8b54548f98588b1bb4c1/88180223311.pdfIn PDF document text
    • https://www.d-table.com/wp-content/plugins/super-forms/uploads/php/files/6b7106dbca403e6ac06b4a0cd1f2e134/14094091065.pdfIn PDF document text
    • http://tehnicgaz.eu/files/file/31406842775.pdfIn PDF document text
    • https://useoneconvo.com/wp-content/plugins/super-forms/uploads/php/files/5d544913f4de23b8a0b1441eb286dc3b/rafazijaf.pdfIn PDF document text
    • https://carpanea.it/wp-content/plugins/super-forms/uploads/php/files/e0d733d57d8d732d856cb402f48e0aa7/61930090571.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/fzgW7-mxBc0/uplcv?utm_term=what+is+a+solid+changing+into+a+liquid+calledPDF 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_off0000ce59.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCE59 10788 bytes
SHA-256: 57582cd617e239322c0b33fe72b87764514d98b2a9175ed4b7c018c30dbef0a0
font_01_sfnt_off0000e6a4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE6A4 16660 bytes
SHA-256: e0f5ce4894e7043661ab7fcb114499026f8c1c673780232867d1b58dc3ba2f5b
font_02_sfnt_off000111ca.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x111CA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1