SB2019061910 - Remote DoS in FreeBSD
Published: June 19, 2019
Security Bulletin ID
SB2019061910
Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Denial of service
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 security vulnerability.
1) Resource exhaustion (CVE-ID: CVE-2019-5599)
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to an error when processing acknowledgements within the TCP loss detection algorithm RACK ("Recent ACKnowledgment"). A remote attacker can trigger resource exhaustion by sending specially crafted TCP packets to the affected system, which causes the several linked lists, used by RACK, to grow unbounded.
Successful exploitation of the vulnerability allows an attacker to perform denial of service attack (lower network performance, consume excessive CPU), but requires that system is compiled with RACK support.
Remediation
Install update from vendor's website.