Malicious PDF — malware analysis report

Static analysis result for SHA-256 88c9953257b34a9b…

MALICIOUS

PDF

76.4 KB Created: 2021-09-13 05:51:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 5b3785b8916e8bda166143f0a595ea04 SHA-1: 2f3bf3c9b6611d98feb7bad3de6a3a0335284a0c SHA-256: 88c9953257b34a9b3379561b63ffc6e88602ec36471c087a698d0eb2988726a6
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous external links, many pointing to compromised CMS uploads or disposable hosting, suggesting a link farm designed to redirect users. The presence of PDF_URI and PDF_SEO_DISPOSABLE_LINK_FARM heuristics further supports this, indicating the PDF's primary function is to drive traffic to potentially malicious external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9908

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://synerhu.ru/uplcv?utm_term=manly+p+hall+pdf PDF link annotation
    • http://interel-rus.ru/test/sites/default/files/file/ditarevilelogut.pdfIn PDF document text
    • https://jatransfer.com/userfiles/file/degenevinowosowiv.pdfIn PDF document text
    • http://demkapi.com/resimler/files/dokozexi.pdfIn PDF document text
    • https://mymovingestimate.com/wp-content/plugins/super-forms/uploads/php/files/40013b695586354c58a7353b1c4e0872/40881384371.pdfIn PDF document text
    • https://www.agcontraincendios.es/ckfinder/userfiles/files/wefatowumemajuzejofope.pdfIn PDF document text
    • https://www.olympusnorge.no/wp-content/plugins/super-forms/uploads/php/files/md59a19003904rpuj33ce8ul7c/99747613580.pdfIn PDF document text
    • https://armour-technoz-ca.otzol.net/ckfinder/userfiles/files/sovuf.pdfIn PDF document text
    • http://ammk.sk/userfiles/file/gojelulofirozujagas.pdfIn PDF document text
    • http://bigcool.net/webroot/img/files/28185895036.pdfIn PDF document text
    • http://lednotice.com/userData/board/file/sigufifogusis.pdfIn PDF document text
    • http://kraski-chernila.ru/resources/file/bedovujafadoxojoses.pdfIn PDF document text
    • https://bentzendesign.se/wp-content/plugins/formcraft/file-upload/server/content/files/1613af451d16af---wujokanabuzeresid.pdfIn PDF document text
    • https://anitt.in/ckfinder/userfiles/files/bejuxotewosefefawu.pdfIn PDF document text
    • http://steinbach.casawell.tw/userfiles/file/mulapoxen.pdfIn PDF document text
    • http://carrollcountylawyers.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/rufosidu.pdfIn PDF document text
    • http://occahomesearch.com/userfiles/files/85839194288.pdfIn PDF document text
    • https://www.fecomerciomg.org.br/wp-content/plugins/formcraft/file-upload/server/content/files/1613583bb8575b---59422211939.pdfIn PDF document text
    • http://tantex.org/tantex/tantexuserfiles/file/xevemazokenix.pdfIn PDF document text
    • http://daiichibus.vn/uploads/news_file/6224158305.pdfIn PDF document text
    • http://transcash.com/ci/userfiles/files/dogekijujumumatovegeguwar.pdfIn PDF document text
    • http://inkjetartandimage.com/Uploads/file/38459693028.pdfIn PDF document text
    • https://thegioidongphuc.net/ckfinder/userfiles/files/teledugowowafaxuzu.pdfIn PDF document text
    • http://www.ncstarim.com.tr/wp-content/plugins/super-forms/uploads/php/files/fs8t63m8t16gdbjb8c1jp8dla7/rejowudosuguwawarires.pdfIn PDF document text
    • https://accidentmatters.com/ckfinder/userfiles/files/28664774955.pdfIn PDF document text
    • http://kubablimel.pl/Image/files/40713975554.pdfIn PDF document text
    • https://www.isgs.org/wp-content/plugins/super-forms/uploads/php/files/32b95a0ac87056d062e542683c3128ce/kumusuxuvibudakejenon.pdfIn PDF document text
    • 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_off0000c95e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC95E 9992 bytes
SHA-256: 7e449716e3cbe1cea0cce52c7dbd61faddf42024a8c6deb5a797c7db6f018d0f
font_01_sfnt_off0000df5e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF5E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f770.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF770 17356 bytes
SHA-256: 7acd4b65b72b54c7dd7fec94d8ff5f83b76ddff536bf7f48b2116f7e960a4128

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