Malicious PDF — malware analysis report

Static analysis result for SHA-256 51b11cbb689df5dd…

MALICIOUS

PDF

74.5 KB Created: 2021-09-24 13:13:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 4c53baa54a0da2ee62c239d993bdc5bb SHA-1: 705916c34ec0f338f34c08d89906ba7bbcf873e0 SHA-256: 51b11cbb689df5dd823a8f56d0f3e122e7f0184466692a1bbb7471fc5c39bb7f
126 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many of which point to disposable domains, and one heuristic identified it as a link farm designed for SEO manipulation. The document body is heavily obfuscated, preventing a clear understanding of its specific lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://casaledellasignora.it/userfiles/files/8013807238.pdf In PDF document text
    • http://aviteksural.ru/admin/ckfinder/userfiles/files/14788166610.pdfIn PDF document text
    • https://nabil-doukali.com/userfiles/file/suvopibumu.pdfIn PDF document text
    • http://movitecnic.com/ressource/site-image/files/96554592350.pdfIn PDF document text
    • http://phayaotechno.com/UserFiles/File/75232966394.pdfIn PDF document text
    • https://narellesastro.com/userfiles/files/21551585869.pdfIn PDF document text
    • https://fivetc.net/uploads/files/12349566071.pdfIn PDF document text
    • https://hankilfood.com/upfile/files/jigapewawegifowexirudut.pdfIn PDF document text
    • http://cnpair.com/userfiles/file/malomodevowarikidowanijal.pdfIn PDF document text
    • http://sbstroy53.ru/img/files/saxosumeboxutanukob.pdfIn PDF document text
    • http://oticonshop.com/ckfinder/userfiles/files/tobanabuvapazemikizugi.pdfIn PDF document text
    • http://zamgph.com/uploads/file/091015122858.pdfIn PDF document text
    • http://ibnuaffan.com/ckfinder/userfiles/files/94947344497.pdfIn PDF document text
    • http://evohome.pl/userfiles/file/josufidut.pdfIn PDF document text
    • http://brmhn.com/userfiles/file/20210907151124_g4v6lv.pdfIn PDF document text
    • http://www.fullmooneye.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f88c049cf5---xinarofifome.pdfIn PDF document text
    • http://ontheedgeofnow.com/wp-content/plugins/formcraft/file-upload/server/content/files/161432470ee986---9152779009.pdfIn PDF document text
    • http://irina-beha.com/ckfinder/userfiles/files/78203986288.pdfIn PDF document text
    • http://sklepjola.pl/userfiles/file/67731452425.pdfIn PDF document text
    • http://madmojo.com/fckupload/file/xonopifiwutimopixuduvajek.pdfIn PDF document text
    • https://sikanderajam.com/Robinson/ckfinder/userfiles/files/69822368853.pdfIn PDF document text
    • http://vom-ragnaroek.de/uploads/file/75956216703.pdfIn PDF document text
    • https://djecijagarderoba.me/userfiles/file/lonununerifupat.pdfIn PDF document text
    • http://sethhukumchandschool.com/userfiles/file/63553240494.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/DOqCt-cVA4I/uplcv?utm_term=clean+up+internal+memory+androidPDF 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_off0000bcab.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBCAB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d4bd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD4BD 18392 bytes
SHA-256: 41d6051698bf7369c2ff2b7ceaac862f32e1b70007f56588b8e6e6006afbaa8f
font_02_sfnt_off00010451.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10451 10632 bytes
SHA-256: 2a3ece0d3fd22303a48967a2c5c50e55f18573bd687172380d5905a72c4d3abf