CVE-2019-9518 : Security Advisory and Response

Certain HTTP/2 implementations are susceptible to a flood of vacant frames, potentially resulting in a denial of service attack. The attacker sends continuous frames with no payload, causing excessive CPU consumption.

Understanding CVE-2019-9518

What is CVE-2019-9518?

Certain HTTP/2 implementations have a susceptibility to a flood of vacant frames, which could possibly result in a denial of service. The attacker sends frames with no payload, leading to excessive CPU consumption.

The Impact of CVE-2019-9518

The vulnerability has a CVSS base score of 7.5 (High) with a high availability impact. It can lead to a denial of service by overwhelming the target with empty frames.

Technical Details of CVE-2019-9518

Vulnerability Description

Vulnerability Type: CWE-400 Uncontrolled Resource Consumption
Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
Scope: Unchanged
User Interaction: None

Affected Systems and Versions

Affected Product: Not applicable
Affected Vendor: Not applicable
Affected Version: Not applicable

Exploitation Mechanism

The attacker sends a continuous stream of frames with no payload and lacking the end-of-stream indicator, such as DATA, HEADERS, CONTINUATION, and PUSH_PROMISE, causing the recipient to consume excessive resources processing each frame.

Mitigation and Prevention

Immediate Steps to Take

Implement network-level protections to filter out malicious traffic targeting HTTP/2 vulnerabilities.
Monitor network traffic for signs of excessive empty frame usage.
Apply patches or updates from relevant vendors to address the vulnerability.

Long-Term Security Practices

Regularly update and patch HTTP/2 implementations to mitigate known vulnerabilities.
Conduct regular security assessments and audits to identify and address potential weaknesses.

Patching and Updates

Refer to vendor advisories and security bulletins for patches and updates related to HTTP/2 implementations.