Vulnerabilities > CVE-2019-20794 - Missing Release of Resource after Effective Lifetime vulnerability in Linux Kernel
Attack vector
LOCAL Attack complexity
HIGH Privileges required
LOW Confidentiality impact
NONE Integrity impact
NONE Availability impact
HIGH Summary
An issue was discovered in the Linux kernel 4.18 through 5.6.11 when unprivileged user namespaces are allowed. A user can create their own PID namespace, and mount a FUSE filesystem. Upon interaction with this FUSE filesystem, if the userspace component is terminated via a kill of the PID namespace's pid 1, it will result in a hung task, and resources being permanently locked up until system reboot. This can result in resource exhaustion.
Vulnerable Configurations
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- HTTP DoS An attacker performs flooding at the HTTP level to bring down only a particular web application rather than anything listening on a TCP/IP connection. This denial of service attack requires substantially fewer packets to be sent which makes DoS harder to detect. This is an equivalent of SYN flood in HTTP. The idea is to keep the HTTP session alive indefinitely and then repeat that hundreds of times. This attack targets resource depletion weaknesses in web server software. The web server will wait to attacker's responses on the initiated HTTP sessions while the connection threads are being exhausted.
References
- http://www.openwall.com/lists/oss-security/2020/08/24/1
- http://www.openwall.com/lists/oss-security/2020/08/24/1
- https://github.com/sargun/fuse-example
- https://github.com/sargun/fuse-example
- https://security.netapp.com/advisory/ntap-20200608-0001/
- https://security.netapp.com/advisory/ntap-20200608-0001/
- https://sourceforge.net/p/fuse/mailman/message/36598753/
- https://sourceforge.net/p/fuse/mailman/message/36598753/