Red Hat Enterprise Linux 8 update for unbound



Published: 2022-11-08
Risk Medium
Patch available YES
Number of vulnerabilities 2
CVE-ID CVE-2022-30698
CVE-2022-30699
CWE-ID CWE-341
Exploitation vector Network
Public exploit N/A
Vulnerable software
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Red Hat Enterprise Linux for ARM 64
Operating systems & Components / Operating system

Red Hat Enterprise Linux for Power, little endian
Operating systems & Components / Operating system

Red Hat Enterprise Linux for IBM z Systems
Operating systems & Components / Operating system

Red Hat Enterprise Linux for x86_64
Operating systems & Components / Operating system

unbound (Red Hat package)
Operating systems & Components / Operating system package or component

Vendor Red Hat Inc.

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) Predictable from Observable State

EUVDB-ID: #VU66548

Risk: Medium

CVSSv3.1:

CVE-ID: CVE-2022-30698

CWE-ID: CWE-341 - Predictable from Observable State

Exploit availability: No

Description

The vulnerability allows a remote attacker to poison DNS cache.

The vulnerability exists due to the way Unbound handles delegation information expiration event. A remote attacker who controls a rouge DNS server can force the Unbound instance to cache incorrect information about subdomain delegation and permanently poison the DNS cache, e.g. perform the "ghost domain names" attack. 

The attack is carried out when Unbound is queried for a subdomain of a rogue domain name. The rogue nameserver returns delegation information for the subdomain that updates Unbound's delegation cache. This action can be repeated before expiry of the delegation information by querying Unbound for a second level subdomain which the rogue nameserver provides new delegation information. Since Unbound is a child-centric resolver, the ever-updating child delegation information can keep a rogue domain name resolvable long after revocation.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux for ARM 64: 8

Red Hat Enterprise Linux for Power, little endian: 8

Red Hat Enterprise Linux for IBM z Systems: 8

Red Hat Enterprise Linux for x86_64: 8.0

unbound (Red Hat package): before 1.16.2-2.el8


CPE2.3 External links

http://access.redhat.com/errata/RHSA-2022:7622

Q & A

Can this vulnerability be exploited remotely?

Is there known malware, which exploits this vulnerability?

2) Predictable from Observable State

EUVDB-ID: #VU66547

Risk: Medium

CVSSv3.1:

CVE-ID: CVE-2022-30699

CWE-ID: CWE-341 - Predictable from Observable State

Exploit availability: No

Description

The vulnerability allows a remote attacker to poison DNS cache.

The vulnerability exists due to the way Unbound handles delegation information expiration event. A remote attacker who controls a rouge DNS server can force the Unbound instance to cache incorrect information about domain delegation and permanently poison the DNS cache, e.g. perform the "ghost domain names" attack. 

The attack is perform when Unbound is queried for a rogue domain name, which cached delegation information is about to expire. The rogue nameserver delays the response until the cached delegation information expires. Upon receiving the delayed answer containing the delegation information, Unbound overwrites the now expired entries.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux for ARM 64: 8

Red Hat Enterprise Linux for Power, little endian: 8

Red Hat Enterprise Linux for IBM z Systems: 8

Red Hat Enterprise Linux for x86_64: 8.0

unbound (Red Hat package): before 1.16.2-2.el8


CPE2.3 External links

http://access.redhat.com/errata/RHSA-2022:7622

Q & A

Can this vulnerability be exploited remotely?

Is there known malware, which exploits this vulnerability?



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