=====[ Tempest Security Intelligence - ADV-9/2017 ]======================== Persistent Cross-Site Scripting (XSS) in Ghost ------------------------------------------------------- Author: - Patrick Costa < patrickrbcosta () gmail.com > Tempest Security Intelligence - Recife, Pernambuco - Brazil =====[ Table of Contents ]================================================= 1. Overview 2. Detailed description 3. Affected versions & Solutions 4. Timeline of disclosure 5. Thanks & Acknowledgements 6. References =====[ Overview ]========================================================== * System affected : Ghost Blog [1] * Version : 0.11.3 previous versions or models may also be affected. [2] * Impact : This vulnerability allows an attacker to use Ghost's platform to deliver attacks against other users. =====[ Detailed description ]============================================== Ghost version 0.11.3 is vulnerable to persistent cross-site scripting (XSS) because it fails to securely handle user data, thus making it possible for an attacker to supply crafted input in order to harm third party users. The affected point is the website input field located within the "Your profile" page. In order to reproduce the vulnerability, access the URL http(s)://{{ blog URL }}/ghost/team/{{ user slug }}/ and edit the user website inserting the following payload: {{ valid URL }}/</script><script>alert(1)</script> Save changes and visit any post created by this author or the author's page at http(s)://{{ blog URL}}/author/{{ user slug }}/. It is worth noting that the issue may affect users regardless of privilege levels, since the malicious page can be browsed by an admin, the owner or a regular visitor. =====[ Aggravating factors ]=============================================== The session token of an authenticated user is accessible through JavaScript. =====[ Affected versions & Solutions ]===================================== The vulnerability is addressed and the fix is part of the 0.11.4 release. =====[ Timeline of disclosure ]============================================ 12/27/2016 - Reported vulnerability to security@ghost.org. 01/10/2017 - Ghost team applied patch. 01/12/2017 - Ghost team answered the email acknowledging the vulnerability. 01/18/2017 - Advisory publication date. =====[ Thanks & Acknowledgements ]========================================= - Tempest Security Intelligence [3] - Tempest Hammerhead Team =====[ References ]======================================================== [1] https://ghost.org/ [2] https://github.com/TryGhost/Ghost/releases/tag/0.11.3 [3] http://www.tempest.com.br/