CVE-2020-22217
Description
A heap buffer over-read flaw was found in c-ares via the ares_parse_soa_reply function in ares_parse_soa_reply.c.
Statement
The attack vector for this flaw initiates from a malicious server (a SOA reply to a client query) which requires a attacker set up a server a make it to be queried by a victim through cache poisoning or MITM, raising the Attack Complexity to High.
This being a out of bounds reads does not bring a risk of memory corruption, which makes it of none impact to Integrity. Also the read limitis 2 bytes (16bit, unsigned short int) from the DNS_QUERY_TYPE MACRO[1] return and the read value would be ignored and not propagated anywhere since the subsequent check would also fail making the confidentiality impact as none.
[1] https://github.com/c-ares/c-ares/blob/4d4fb34075c90d8f2f9ff81890152ab60f65e48e/include/ares_dns.h#L95 [2] https://github.com/c-ares/c-ares/issues/333
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.9 | 5.9 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | High | High | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
Confidentiality
Technical Impact: Bypass Protection Mechanism
By reading out-of-bounds memory, an attacker might be able to get secret values, such as memory addresses, which can bypass protection mechanisms such as ASLR in order to improve the reliability and likelihood of exploiting a separate weakness to achieve code execution instead of just denial of service.
Availability,Integrity
Technical Impact: DoS: Crash, Exit, or Restart
An attacker might be able to cause a crash or other denial of service by causing the product to read a memory location that is not allowed (such as a segmentation fault), or to cause other conditions in which the read operation returns more data than is expected.
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