Cross-site Scripting (XSS)
Affecting sinatra gem, versions <1.4.6, >=1.4.0.a
sinatra is a DSL for quickly creating web applications in Ruby with minimal effort.
Affected versions of the package are vulnerable to reflected Cross-site Scripting (XSS). This occurs on the development 404 page, which does not validate the request path. This may allow attackers to create a specially crafted request that would execute arbitrary script code.
These attacks are possible by escaping the context of the web application and injecting malicious scripts in an otherwise trusted website. These scripts can introduce additional attributes (say, a "new" option in a dropdown list or a new link to a malicious site) and can potentially execute code on the clients side, unbeknown to the victim. This occurs when characters like \< > \" \' are not escaped properly.
There are a few types of XSS:
- Persistent XSS is an attack in which the malicious code persists into the web app’s database.
- Reflected XSS is an which the website echoes back a portion of the request. The attacker needs to trick the user into clicking a malicious link (for instance through a phishing email or malicious JS on another page), which triggers the XSS attack.
You can read more about
Cross-site Scripting (XSS) on our blog.
sinatra to version 1.4.6 or higher.
Do your applications use this vulnerable package?
- Andy Brody
- Snyk ID
- 11 Jun, 2014
- 10 Jan, 2018