Malicious PDF — malware analysis report

Static analysis result for SHA-256 1b4c8a3842298102…

MALICIOUS

PDF

70.1 KB Created: 2021-09-28 22:11:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: f418bd249a190ce6a4abe97545c0f0a4 SHA-1: a4c12ca66e46ec78dd1bcb86c7d233a5f6a019a9 SHA-256: 1b4c8a3842298102eb7ace04d662c21265cabac402e9779ebbbe53a4a906e8e2
156 Risk Score

Malware Insights

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

The PDF was flagged by ClamAV as Pdf.Phishing.Trojan and an ML classifier indicated a high probability of maliciousness. Heuristics identified it as a link farm, with many embedded URLs pointing to various domains, some of which are hosted on compromised CMS upload storage. The primary purpose appears to be redirecting users through a series of links, likely to a phishing page or to download a secondary payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

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://stka.gr/ckfinder/userfiles/files/risaselisaga.pdf In PDF document text
    • http://banglatalkies.com/dynamic-images/cms/file/97303244902.pdfIn PDF document text
    • https://er-cardiff.com/eurostyl/photos/file/37174890771.pdfIn PDF document text
    • http://nscenter.cn/upload/files/83935805972.pdfIn PDF document text
    • http://www.unidacardoso.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1613381279d828---81803482572.pdfIn PDF document text
    • http://easytravel63.ru/ckfinder/userfiles/files/55500680046.pdfIn PDF document text
    • http://foire-fromages-et-vins.com/wp-content/plugins/formcraft/file-upload/server/content/files/161479e5a047f8---95910520365.pdfIn PDF document text
    • https://euinsuti.uniluxgym.ro/app/webroot/files/userfiles/files/xatasifuzejulurur.pdfIn PDF document text
    • https://krafteco.ru/uploads/files/ditobutanomesotemawezaboz.pdfIn PDF document text
    • http://3m18.com/images/editor/files/35549001711.pdfIn PDF document text
    • http://studioriboldi.eu/userfiles/files/posapuxivadagametisa.pdfIn PDF document text
    • https://www.luxboss.com/ckfinder/userfiles/files/20202612437.pdfIn PDF document text
    • http://hosungtour.net/FileData/ckfinder/files/20210924_DF529F56262B8FF1.pdfIn PDF document text
    • http://mallenmediations.com/mallenmediations/images/userfiles/file/47590384723.pdfIn PDF document text
    • http://le-nora.com/userfiles/file/13672084727.pdfIn PDF document text
    • http://membranekeyboard.pl/_data/file/fojepololake.pdfIn PDF document text
    • http://uco-kampen.com/media/files/mufibixezesatelulaf.pdfIn PDF document text
    • https://learningsolution.ca/userfiles/files/97014253110.pdfIn PDF document text
    • https://brylka-kfz.de/wp-content/plugins/formcraft/file-upload/server/content/files/16133140366c11---jotemabupukuda.pdfIn PDF document text
    • https://www.gs-gleichmann.de/wp-content/plugins/formcraft/file-upload/server/content/files/16146a205977a7---newona.pdfIn PDF document text
    • http://hyeminshop.com/DATA/files/fuwasubibubagekemililosus.pdfIn PDF document text
    • http://e-skala.pl/userfiles/file/89448037488.pdfIn PDF document text
    • http://studiotecnicoprato.eu/userfiles/files/68697431289.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/Om9ozkHLxGw/uplcv?utm_term=daisy+the+dinosaur+for+pcPDF 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_off0000b054.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB054 10888 bytes
SHA-256: 99d7bcac76186f0539964a503ca18f98b2f16097bfaa9691107c8ac051617839
font_01_sfnt_off0000c980.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC980 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000e192.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE192 15752 bytes
SHA-256: d8f3280d52d3990de58bf797bc7c105f103ff316991779b2208ae82d7436d989