Malicious PDF — malware analysis report

Static analysis result for SHA-256 cbbbfef5855a3aae…

MALICIOUS

PDF

96.1 KB Created: 2021-09-09 18:55:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 22cda3f4975bc513feef871bf1e53a26 SHA-1: 0f38e91a1af2a27d60832aa7e8ff93ce0ba18213 SHA-256: cbbbfef5855a3aaea847d899bb9931fe8d1e8a8e0f325bb8a432371edd77e60f
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ML classifiers and ClamAV, specifically identified as a phishing trojan. It contains numerous external URIs and is flagged as a link farm on disposable hosting, indicating a likely phishing or malware distribution attempt. Although no scripts were explicitly extracted, the PDF structure and embedded URIs suggest it's designed to redirect users to malicious websites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9988

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 https://infrive.ru/uplcv?utm_term=english+file+elementary+workbook+third+edition+pdf+download PDF link annotation
    • https://uslugiinzynierskie.com/eurostyl/photos/file/xajobufinulogufer.pdfIn PDF document text
    • http://sntaviator.ru/ckfinder/userfiles/files/bewipe.pdfIn PDF document text
    • http://fkjz.cn/upload/files/2021/09/202109021809092485.pdfIn PDF document text
    • http://serbanindustrialconstruct.ro/uploads/files/78952201163.pdfIn PDF document text
    • https://efckrakow.pl/userfiles/file/37705764111.pdfIn PDF document text
    • http://cornucopiafrederick.com/uploads/files/nugajesaw.pdfIn PDF document text
    • https://cfaegaianascente.pt/portal/userfiles/files/12356910219.pdfIn PDF document text
    • https://realimpacto.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1613562eb058cf---napexupuzage.pdfIn PDF document text
    • https://nexusmediation.nl/files/94887918214.pdfIn PDF document text
    • http://khaskhaan.mn/uploads/userfiles/files/92850965382.pdfIn PDF document text
    • https://youkuvpn.com/upload/files/ligugep.pdfIn PDF document text
    • https://concurs-euclid.ro/upload/fck/99334106580.pdfIn PDF document text
    • http://aerotechgroup.ru/img/outer/files/dexopi.pdfIn PDF document text
    • https://rts-wm.com/ckfinder/userfiles/files/sixino.pdfIn PDF document text
    • http://julianowka.pl/ckfinder/userfiles/files/zipane.pdfIn PDF document text
    • https://fullgame.hu/uploads/files/jenebebuvubetiwulo.pdfIn PDF document text
    • http://techsystem.gr/data/uploads/ckeditor/files/75750768574.pdfIn PDF document text
    • http://abarappresentanze.it/userfiles/files/29235636825.pdfIn PDF document text
    • https://vinacomvietnam.vn/uploads/news_file/58401885343.pdfIn PDF document text
    • http://stin-verdon.fr/assets/Image/files/tuxidapopirabifulu.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_off00010579.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10579 22568 bytes
SHA-256: 33bef222eeba516df16d52368803288931607a032b8abd8de71dacf1492883d9
font_01_sfnt_off00014020.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14020 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00015837.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15837 11360 bytes
SHA-256: 60d4713adda2b54cb9c1380ec3f765ec2ce15906100bf4aba4868a931f8979ff

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