Python CVE-2019-16935 CRLF Multiple Cross Site Scripting Vulnerabilities

Description

Python is prone to multiple cross-site scripting vulnerabilities because it fails to sanitize user-supplied input. An attacker may leverage these issues to execute arbitrary script code in the browser of an unsuspecting user in the context of the affected site. This may allow the attacker to steal cookie-based authentication credentials and launch other attacks. Python versions through 2.7.16, 3.x through 3.6.9 and 3.7.x through 3.7.4 are vulnerable.

Technologies Affected

• Python Software Foundation Python 2.0.0
• Python Software Foundation Python 2.0.1
• Python Software Foundation Python 2.1.0
• Python Software Foundation Python 2.1.1
• Python Software Foundation Python 2.1.2
• Python Software Foundation Python 2.1.3
• Python Software Foundation Python 2.2
• Python Software Foundation Python 2.2.0
• Python Software Foundation Python 2.2.1
• Python Software Foundation Python 2.2.2
• Python Software Foundation Python 2.2.3
• Python Software Foundation Python 2.3
• Python Software Foundation Python 2.3.0
• Python Software Foundation Python 2.3.1
• Python Software Foundation Python 2.3.2
• Python Software Foundation Python 2.3.3
• Python Software Foundation Python 2.3.4
• Python Software Foundation Python 2.3.5
• Python Software Foundation Python 2.3.6
• Python Software Foundation Python 2.3.7
• Python Software Foundation Python 2.4
• Python Software Foundation Python 2.4.0
• Python Software Foundation Python 2.4.1
• Python Software Foundation Python 2.4.2
• Python Software Foundation Python 2.4.2
• Python Software Foundation Python 2.4.3
• Python Software Foundation Python 2.4.4
• Python Software Foundation Python 2.4.5
• Python Software Foundation Python 2.4.6
• Python Software Foundation Python 2.5
• Python Software Foundation Python 2.5.1
• Python Software Foundation Python 2.5.150
• Python Software Foundation Python 2.5.2
• Python Software Foundation Python 2.5.3
• Python Software Foundation Python 2.5.4
• Python Software Foundation Python 2.5.5
• Python Software Foundation Python 2.5.6
• Python Software Foundation Python 2.6
• Python Software Foundation Python 2.6.1
• Python Software Foundation Python 2.6.2
• Python Software Foundation Python 2.6.4
• Python Software Foundation Python 2.6.5
• Python Software Foundation Python 2.6.6
• Python Software Foundation Python 2.6.7
• Python Software Foundation Python 2.6.8
• Python Software Foundation Python 2.7
• Python Software Foundation Python 2.7.0
• Python Software Foundation Python 2.7.1
• Python Software Foundation Python 2.7.10
• Python Software Foundation Python 2.7.11
• Python Software Foundation Python 2.7.12
• Python Software Foundation Python 2.7.13
• Python Software Foundation Python 2.7.14
• Python Software Foundation Python 2.7.15
• Python Software Foundation Python 2.7.16
• Python Software Foundation Python 2.7.2
• Python Software Foundation Python 2.7.3
• Python Software Foundation Python 2.7.4
• Python Software Foundation Python 2.7.5
• Python Software Foundation Python 2.7.6
• Python Software Foundation Python 2.7.7
• Python Software Foundation Python 2.7.8
• Python Software Foundation Python 2.7.9
• Python Software Foundation Python 3.0.1
• Python Software Foundation Python 3.1
• Python Software Foundation Python 3.1.1
• Python Software Foundation Python 3.1.2
• Python Software Foundation Python 3.1.3
• Python Software Foundation Python 3.1.4
• Python Software Foundation Python 3.1.5
• Python Software Foundation Python 3.2
• Python Software Foundation Python 3.2.0
• Python Software Foundation Python 3.2.1
• Python Software Foundation Python 3.2.2
• Python Software Foundation Python 3.2.2150
• Python Software Foundation Python 3.2.3
• Python Software Foundation Python 3.2.4
• Python Software Foundation Python 3.2.5
• Python Software Foundation Python 3.2.6
• Python Software Foundation Python 3.3
• Python Software Foundation Python 3.3.0
• Python Software Foundation Python 3.3.1
• Python Software Foundation Python 3.3.1 Rc1
• Python Software Foundation Python 3.3.2
• Python Software Foundation Python 3.3.3
• Python Software Foundation Python 3.3.3 Rc1
• Python Software Foundation Python 3.3.3 Rc2
• Python Software Foundation Python 3.3.4
• Python Software Foundation Python 3.3.4 Rc1
• Python Software Foundation Python 3.3.5 -
• Python Software Foundation Python 3.3.5 Rc1
• Python Software Foundation Python 3.3.5 Rc2
• Python Software Foundation Python 3.3.6 Rc1
• Python Software Foundation Python 3.4
• Python Software Foundation Python 3.4.0
• Python Software Foundation Python 3.4.1
• Python Software Foundation Python 3.4.10
• Python Software Foundation Python 3.4.2
• Python Software Foundation Python 3.4.3
• Python Software Foundation Python 3.4.4
• Python Software Foundation Python 3.4.5
• Python Software Foundation Python 3.4.6
• Python Software Foundation Python 3.4.7
• Python Software Foundation Python 3.4.8
• Python Software Foundation Python 3.4.9
• Python Software Foundation Python 3.5
• Python Software Foundation Python 3.5.0
• Python Software Foundation Python 3.5.1
• Python Software Foundation Python 3.5.2
• Python Software Foundation Python 3.5.3
• Python Software Foundation Python 3.5.4
• Python Software Foundation Python 3.5.5
• Python Software Foundation Python 3.5.6
• Python Software Foundation Python 3.5.7
• Python Software Foundation Python 3.6
• Python Software Foundation Python 3.6.0
• Python Software Foundation Python 3.6.1
• Python Software Foundation Python 3.6.2
• Python Software Foundation Python 3.6.3
• Python Software Foundation Python 3.6.4
• Python Software Foundation Python 3.6.5
• Python Software Foundation Python 3.6.6
• Python Software Foundation Python 3.6.7
• Python Software Foundation Python 3.6.8
• Python Software Foundation Python 3.6.9
• Python Software Foundation Python 3.7.0
• Python Software Foundation Python 3.7.1
• Python Software Foundation Python 3.7.2
• Python Software Foundation Python 3.7.3
• Python Software Foundation Python 3.7.4

Recommendations

Block external access at the network boundary, unless external parties require service.
If global access isn’t needed, filter access to the affected computer at the network boundary. Restricting access to only trusted computers and networks might greatly reduce the likelihood of successful exploits.

Run all software as a nonprivileged user with minimal access rights.
To reduce the impact of latent vulnerabilities, always run nonadministrative software as an unprivileged user with minimal access rights.

Deploy network intrusion detection systems to monitor network traffic for malicious activity.
Deploy NIDS to monitor network traffic for signs of anomalous or suspicious activity including unexplained incoming and outgoing traffic. This may indicate exploit attempts or activity that results from successful exploits.

Do not follow links provided by unknown or untrusted sources.
Web users should be cautious about following links to sites that are provided by unfamiliar or suspicious sources. Filtering HTML from emails may help remove a possible vector for transmitting malicious links to users.

Set web browser security to disable the execution of JavaScript.
Since a successful exploit of these issues allows malicious code to execute in web clients, consider disabling support for script code and active content within the client browser. Note that this mitigation tactic might adversely affect legitimate websites that rely on the execution of browser-based script code.

Updates are available. Please see the references or vendor advisory for more information.