Malicious PDF — malware analysis report

Static analysis result for SHA-256 5cbee6664c633926…

MALICIOUS

PDF

76.2 KB Created: 2021-09-03 04:53:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 1b4d3e86b979c29a51160063f8b5775e SHA-1: 3bc014c0924af7b827945a25337c24ba94aa16b3 SHA-256: 5cbee6664c633926bea7cc11b22052a218e1fc384af6a573a3d57ae97af2d2b9
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF contains a link farm pointing to numerous external PDF files hosted on various domains, some of which are identified as compromised CMS uploads or disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. No scripts were extracted, but the structure suggests a lure to external malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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 http://yuhongzg.com/d/files/jedotebimosujemeporab.pdf In PDF document text
    • http://aliceinformaticasrl.com/user/pages/29306324159.pdfIn PDF document text
    • https://cristalensi.com/public/File/60780629828.pdfIn PDF document text
    • http://premium-h.info/files/files/91566590211.pdfIn PDF document text
    • https://webupdate.ca/wp-content/plugins/super-forms/uploads/php/files/1k604kjsg2l58vrifmaa9dlp2r/72943454739.pdfIn PDF document text
    • https://hotel-la-licorne.fr/userfiles/file/wukijokiminitabowefi.pdfIn PDF document text
    • https://digireg.se/upload/tidifuf.pdfIn PDF document text
    • https://greenlakepaint.com/ckfinder/userfiles/files/rebexubaleluno.pdfIn PDF document text
    • https://oknoplus-omsk.ru/wp-content/plugins/super-forms/uploads/php/files/10478c8d7d6689797131da9168ec1051/30711656645.pdfIn PDF document text
    • https://agilitynd.com/wp-content/plugins/super-forms/uploads/php/files/4389ce22a6e695d6be9adb7eea96353d/95007952605.pdfIn PDF document text
    • http://worshipedia.net/sites/default/files/file/24985926164.pdfIn PDF document text
    • http://nokianhakkablue.ru/ckfinder/userfiles/files/1167818139.pdfIn PDF document text
    • https://stayinbranson.com/ckfinder/triplebuserfiles/file/fabopexidefav.pdfIn PDF document text
    • http://tinhdauvietnam.vn/upload/files/zenejixe.pdfIn PDF document text
    • https://andymullinscommercial.com/home/andy/public_html/ckfinder/userfiles/files/67523728446.pdfIn PDF document text
    • https://alistairmills.com/ckfinder/userfiles/files/85857885034.pdfIn PDF document text
    • https://www.pfgpartners.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1607cadb952343---zumufadedoxatip.pdfIn PDF document text
    • https://alihuata.com/userfiles/file/39572004235.pdfIn PDF document text
    • http://j-club.eu/userfiles/file/33296014290.pdfIn PDF document text
    • https://sanmall.ru/files/uploads/files/61385249331.pdfIn PDF document text
    • https://kopari.hu/files/file/14044242023.pdfIn PDF document text
    • https://brunoamaranti.it/wp-content/plugins/super-forms/uploads/php/files/p3e1d5g530nvle4r0j9f4t8no5/sawixo.pdfIn PDF document text
    • http://tznjl.com/userfiles/files/54913279880.pdfIn PDF document text
    • http://kenshopvn.com/uploads/files/85444310213.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/cv9VXjIrmdE/uplcv?utm_term=cardiovascular+system+worksheet+keyPDF 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_off0000c541.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC541 16964 bytes
SHA-256: ecc7b9bed30fe780ca0e512f72f55a9d89ea84bda189c1340a2b100b37ff8d05
font_01_sfnt_off0000f126.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF126 11020 bytes
SHA-256: 72cae46ff4c78fbc55d682ef1f200f2c69b663b7eef08d1acbfb3d03ddb54846
font_02_sfnt_off00010aec.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10AEC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1