Symfony CVE-2019-18889 Multiple Remote Code Execution Vulnerabilities

Description

Symfony is prone to multiple remote code-execution vulnerabilities. Successfully exploiting these issues may result in the execution of arbitrary code in the context of the affected application. Failed exploit attempts will likely result in denial-of-service conditions. Symfony versions 3.4.0 through 3.4.34, 4.2.0 through 4.2.11 and 4.3.0 through 4.3.7 are vulnerable.

Technologies Affected

• SensioLabs Symfony 3.4.0
• SensioLabs Symfony 3.4.13
• SensioLabs Symfony 3.4.14
• SensioLabs Symfony 3.4.19
• SensioLabs Symfony 3.4.20
• SensioLabs Symfony 3.4.25
• SensioLabs Symfony 3.4.26
• SensioLabs Symfony 3.4.34
• SensioLabs Symfony 4.2.0
• SensioLabs Symfony 4.2.1
• SensioLabs Symfony 4.2.11
• SensioLabs Symfony 4.2.6
• SensioLabs Symfony 4.2.7
• SensioLabs Symfony 4.3.0
• SensioLabs Symfony 4.3.7

Recommendations

Block external access at the network boundary, unless external parties require service.
If possible, block external access to the server hosting the vulnerable software. Permit access for trusted or internal networks and computers only.

Run all software as a nonprivileged user with minimal access rights.
Running server processes with minimal privileges and within a restricted environment using facilities such as chroot or jail may limit the consequences of successful attacks.

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. This may indicate exploit attempts or activity that results from successful exploits.

Implement multiple redundant layers of security.
Memory-protection schemes (such as nonexecutable stack and heap configurations and randomly mapped memory segments) will complicate exploits of remote code-execution vulnerabilities.

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