Malicious PDF — malware analysis report

Static analysis result for SHA-256 cbd233bbe051a9b7…

MALICIOUS

PDF

83.0 KB Created: 2021-09-13 15:59:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 6b7f00149fd8e4dc2f2f49733056d57c SHA-1: c5466690ca6071366de521c353f9111683f9a3ce SHA-256: cbd233bbe051a9b7b0f7c767e1a4eb36bb8dfcd45f2a577f2da7c343d6946052
174 Risk Score

Malware Insights

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

The PDF document exhibits characteristics of a phishing lure, specifically prompting the user to install a browser extension or update under the guise of urgency. While no executable scripts were directly extracted, the presence of numerous external URLs and the ML classifier's high confidence score suggest malicious intent. The ClamAV detection further supports this, identifying the file as Pdf.Phishing.Trojan.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9833

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • Browser extension / update installation lure high SE_BROWSER_INSTALL_LURE
    Document tells the user to install a browser extension, plugin, viewer, or browser update to view content — a common social-engineering path for credential theft and malware installation
  • 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.
  • Urgency / deadline lure low SE_URGENCY_LURE
    Document contains urgency or deadline language ('account will be terminated', 'action required within 24 hours', etc.) — useful context, but low-signal without other findings
  • 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://thunderstar.cn/userfiles/file/20210910075501592764506.pdf
    • https://kga-am-adlergestell-ev.de/kga/ckfinder/userfiles/files/77630350223.pdf
    • http://shbaicun.com/userfiles/file/2021090812343473499.pdf
    • https://www.studioline.ie/ckfinder/userfiles/files/tonipinemalem.pdf
    • https://johanbjerke.se/userfiles/file/fovanusol.pdf
    • http://cerrutistudio.eu/userfiles/files/44200173106.pdf
    • http://websurin.net/UserFiles/File/80262256349.pdf
    • https://newegys.egyseg.eu/ckfinder/userfiles/files/mavij.pdf
    • http://smcertificationservices.com/userfiles/files/zokugegonogitizelogod.pdf
    • http://beganijewellers.com/ckeditor/ckfinder/userfiles/files/35641893325.pdf
    • https://homestayhoian.vn/uploads/image/files/zasejabadulegosub.pdf
    • http://cukiernia-waltar.pl/qcms/userfiles/file/zofojetopemopajiwowosu.pdf
    • http://www.anapharmata.hu/ckfinder/core/connector/php/files/1708724312.pdf
    • http://trungtamdaykem.vn/Images_upload/files/61761433871.pdf
    • https://tonitomov.com/picture/file/damapimugopoxij.pdf
    • http://miyagi.chi-kara.net/Upload/files/lagezujefizunibakujegew.pdf
    • https://mpksieradz.pl/upload/file/48255745323.pdf
    • https://www.accidentinjurylascruces.com/wp-content/plugins/super-forms/uploads/php/files/lo5q9ej496q83q3clm9r86420m/43650211142.pdf
    • http://wmc21.com/ckupload/files/rifowidaza.pdf
    • http://constantemails.com/userfiles/file/163084023528754285851.pdf
    • https://csn-alliance.com/data/files/muduvapil.pdf
    • https://debo-fit.be/userfiles/file///92984359175.pdf
    • http://g-shocktou.com/user_file/file/munabefasase.pdf
    • https://sanruouvang.net/images/uploaded/file/80820423940.pdf
    • https://amesmedicalservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613b1d1eb62e4---58763181518.pdf
    • http://xn----7sbbbizu2bxaod.xn--p1ai/userfiles/file/49170072641.pdf
    • http://ankamet.com/userfiles/file/12799957545.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/LPIa9PGmDLg/uplcv?utm_term=robux+free+generator+no+human+verification
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000def0.bin
6c7e6f20a0ec5c1fa3a1067849ba1e6a15c5605bcf76b72184e455aa6361b5c0
pdf-font-stream PDF embedded font (sfnt) at offset 0xDEF0 17756 bytes
font_01_sfnt_off00010c7c.bin
2b797bbcdc954ce44e3668f59521413f41ded3e3a06d01fc946b0c1912e3c2db
pdf-font-stream PDF embedded font (sfnt) at offset 0x10C7C 11020 bytes
font_02_sfnt_off00012608.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x12608 16792 bytes