CVE-2019-11939 : Exploit Details and Defense Strategies

Facebook Thrift servers written in Golang prior to v2020.03.16.00 are vulnerable to a denial of service attack due to improper handling of message sizes.

Understanding CVE-2019-11939

This CVE describes a vulnerability in Facebook Thrift servers that could be exploited by malicious clients to trigger denial of service attacks.

What is CVE-2019-11939?

Facebook Thrift servers written in Golang did not handle messages declaring container sizes larger than the payload correctly, allowing for potential denial of service attacks by malicious clients.

The Impact of CVE-2019-11939

The vulnerability in Facebook Thrift servers could lead to denial of service attacks by causing large memory allocations with small messages.

Technical Details of CVE-2019-11939

Facebook Thrift servers written in Golang were susceptible to a denial of service vulnerability due to improper handling of message sizes.

Vulnerability Description

Previous versions of Facebook Thrift servers in Golang did not properly handle messages with container sizes larger than the actual payload, potentially leading to denial of service attacks.

Affected Systems and Versions

Product: Facebook Thrift
Vendor: Facebook
Affected Versions: Versions prior to v2020.03.16.00

Exploitation Mechanism

Malicious clients could exploit this flaw by sending small messages that would trigger large memory allocations, potentially causing denial of service.

Mitigation and Prevention

It is crucial to take immediate steps to address and prevent the exploitation of CVE-2019-11939.

Immediate Steps to Take

Update Facebook Thrift servers to version v2020.03.16.00 or newer to mitigate the vulnerability.
Monitor and restrict incoming message sizes to prevent malicious exploitation.

Long-Term Security Practices

Regularly update and patch Facebook Thrift servers to ensure the latest security fixes are in place.
Implement proper input validation mechanisms to prevent similar vulnerabilities in the future.

Patching and Updates

Apply patches provided by Facebook for Facebook Thrift servers to address the vulnerability and enhance security measures.