Malicious PDF — malware analysis report

Static analysis result for SHA-256 53f8bd427bb0876b…

MALICIOUS

PDF

82.7 KB Created: 2021-10-08 10:56:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 7732dcb63dccfb376e87703bf2c1d68c SHA-1: 69f83bf610cb83acd92453fc19fb50e7cd2217d4 SHA-256: 53f8bd427bb0876bfdf2d24d36fdbc61f68f24fa17e2216d35f36de925500038
66 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous embedded URLs, many of which point to suspicious domains and are flagged as part of a link farm. The ML classifier strongly indicates maliciousness, and the PDF structure suggests it's designed to lure users to external sites, potentially for further exploitation or phishing. No scripts were extracted, but the high number of external links and the ML detection point to a malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

Heuristics 4

  • 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://pvesc.vn/uploaded/file/wetavujifu.pdf In PDF document text
    • https://piphoto.tw/uploads/files/202110051844432572.pdfIn PDF document text
    • http://peter-crooks.com/userfiles/file/fejuwu.pdfIn PDF document text
    • http://sxsasa.org/images_fck/file/1631353362.pdfIn PDF document text
    • https://mabuksusu.com/contents/files/marukabenevi.pdfIn PDF document text
    • http://conblocmanado.com/pics/file/48945076298.pdfIn PDF document text
    • http://midesignvn.com/uploads/files/xipoz.pdfIn PDF document text
    • https://nghiepvu.udicmanpower.vn/uploads/news_file/47141007166.pdfIn PDF document text
    • http://neoclassicalmansions.com/uplds/file/resivumosuj.pdfIn PDF document text
    • http://cnhhgj.com/upfiles/userfiles/file/ligesiferule.pdfIn PDF document text
    • http://balbu.eu/uploads/news/file/17127650179.pdfIn PDF document text
    • http://squash-fitness.cz/userfiles/file/39138280808.pdfIn PDF document text
    • http://ossokahve.com/upload/file/65900873046.pdfIn PDF document text
    • http://soles2walk.com/data/file/nadafi.pdfIn PDF document text
    • http://suarezbeltran.com/aym_images/files/88536600742.pdfIn PDF document text
    • http://bellezaeimagen.com.mx/wp-content/plugins/formcraft/file-upload/server/content/files/1613544579c05c---beripurumi.pdfIn PDF document text
    • https://eminenceconstruction.ca/viking1/uploads/files/24778464974.pdfIn PDF document text
    • https://stgeorgedentalcare.in/ckfinder/userfiles/files/69355946889.pdfIn PDF document text
    • https://langumeistras.lt/i/File/widapivelupobe.pdfIn PDF document text
    • https://emergent-partners.com/wp-content/plugins/formcraft/file-upload/server/content/files/161537c91b704d---mifuj.pdfIn PDF document text
    • https://bahispesinde.com/gnc/veri/_files/33943298416.pdfIn PDF document text
    • https://kluchar.net/klucharnet/images/file/zobuzozuj.pdfIn PDF document text
    • http://cuanhuadanang.vn/uploads/image/files/saboratobiki.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/ngfLrbzwjls/uplcv?utm_term=dogs+with+five+toesPDF 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_off0000db8b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB8B 19492 bytes
SHA-256: e1d2083da56959cdebb547a7193b0fad2cb78c6f7f5b9eaa52e92aea8acbe4b9
font_01_sfnt_off00010e9c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10E9C 10232 bytes
SHA-256: c27456d91443b54e02bc32a7720b11fc286d81a5e8f002ce945fc488759be02f
font_02_sfnt_off000125d2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x125D2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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