Vulnerabilities > CVE-2019-5023 - Missing Release of Resource after Effective Lifetime vulnerability in Opensrcsec Grsecurity and PAX
Attack vector
NETWORK Attack complexity
MEDIUM Privileges required
NONE Confidentiality impact
NONE Integrity impact
NONE Availability impact
PARTIAL Summary
An exploitable vulnerability exists in the grsecurity PaX patch for the function read_kmem, in PaX from version pax-linux-4.9.8-test1 to 4.9.24-test7, grsecurity official from version grsecurity-3.1-4.9.8-201702060653 to grsecurity-3.1-4.9.24-201704252333, grsecurity unofficial from version v4.9.25-unofficialgrsec to v4.9.74-unofficialgrsec. PaX adds a temp buffer to the read_kmem function, which is never freed when an invalid address is supplied. This results in a memory leakage that can lead to a crash of the system. An attacker needs to induce a read to /dev/kmem using an invalid address to exploit this vulnerability.
Vulnerable Configurations
| Part | Description | Count |
|---|---|---|
| Application | 6 |
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.
Talos
| id | TALOS-2019-0784 |
| last seen | 2019-11-07 |
| published | 2019-05-29 |
| reporter | Talos Intelligence |
| source | http://www.talosintelligence.com/vulnerability_reports/TALOS-2019-0784 |
| title | PaX read_kmem denial of service vulnerability |