Amazon Linux AMI update for unbound



Published: 2024-08-06
Risk Medium
Patch available YES
Number of vulnerabilities 3
CVE-ID CVE-2022-30698
CVE-2022-30699
CVE-2022-3204
CWE-ID CWE-341
CWE-400
Exploitation vector Network
Public exploit N/A
Vulnerable software
Subscribe 		Amazon Linux AMI
Operating systems & Components / Operating system

unbound
Operating systems & Components / Operating system package or component

Vendor Amazon Web Services

Security Bulletin

This security bulletin contains information about 3 vulnerabilities.

1) Predictable from Observable State

EUVDB-ID: #VU66548

Risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N/E:U/RL:O/RC:C]

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

Update the affected packages:

aarch64:
    unbound-debuginfo-1.16.3-2.amzn2023.0.1.aarch64
    python3-unbound-debuginfo-1.16.3-2.amzn2023.0.1.aarch64
    unbound-utils-debuginfo-1.16.3-2.amzn2023.0.1.aarch64
    unbound-debugsource-1.16.3-2.amzn2023.0.1.aarch64
    unbound-utils-1.16.3-2.amzn2023.0.1.aarch64
    unbound-libs-debuginfo-1.16.3-2.amzn2023.0.1.aarch64
    unbound-libs-1.16.3-2.amzn2023.0.1.aarch64
    unbound-anchor-1.16.3-2.amzn2023.0.1.aarch64
    python3-unbound-1.16.3-2.amzn2023.0.1.aarch64
    unbound-anchor-debuginfo-1.16.3-2.amzn2023.0.1.aarch64
    unbound-devel-1.16.3-2.amzn2023.0.1.aarch64
    unbound-1.16.3-2.amzn2023.0.1.aarch64

src:
    unbound-1.16.3-2.amzn2023.0.1.src

x86_64:
    unbound-debuginfo-1.16.3-2.amzn2023.0.1.x86_64
    unbound-utils-debuginfo-1.16.3-2.amzn2023.0.1.x86_64
    unbound-libs-debuginfo-1.16.3-2.amzn2023.0.1.x86_64
    unbound-libs-1.16.3-2.amzn2023.0.1.x86_64
    python3-unbound-debuginfo-1.16.3-2.amzn2023.0.1.x86_64
    python3-unbound-1.16.3-2.amzn2023.0.1.x86_64
    unbound-1.16.3-2.amzn2023.0.1.x86_64
    unbound-anchor-1.16.3-2.amzn2023.0.1.x86_64
    unbound-anchor-debuginfo-1.16.3-2.amzn2023.0.1.x86_64
    unbound-utils-1.16.3-2.amzn2023.0.1.x86_64
    unbound-devel-1.16.3-2.amzn2023.0.1.x86_64
    unbound-debugsource-1.16.3-2.amzn2023.0.1.x86_64

Vulnerable software versions

Amazon Linux AMI: All versions

unbound: before 1.16.3-2

CPE2.3 External links

http://alas.aws.amazon.com/AL2023/ALAS-2023-078.html


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

2) Predictable from Observable State

EUVDB-ID: #VU66547

Risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N/E:U/RL:O/RC:C]

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

Update the affected packages:

aarch64:
    unbound-debuginfo-1.16.3-2.amzn2023.0.1.aarch64
    python3-unbound-debuginfo-1.16.3-2.amzn2023.0.1.aarch64
    unbound-utils-debuginfo-1.16.3-2.amzn2023.0.1.aarch64
    unbound-debugsource-1.16.3-2.amzn2023.0.1.aarch64
    unbound-utils-1.16.3-2.amzn2023.0.1.aarch64
    unbound-libs-debuginfo-1.16.3-2.amzn2023.0.1.aarch64
    unbound-libs-1.16.3-2.amzn2023.0.1.aarch64
    unbound-anchor-1.16.3-2.amzn2023.0.1.aarch64
    python3-unbound-1.16.3-2.amzn2023.0.1.aarch64
    unbound-anchor-debuginfo-1.16.3-2.amzn2023.0.1.aarch64
    unbound-devel-1.16.3-2.amzn2023.0.1.aarch64
    unbound-1.16.3-2.amzn2023.0.1.aarch64

src:
    unbound-1.16.3-2.amzn2023.0.1.src

x86_64:
    unbound-debuginfo-1.16.3-2.amzn2023.0.1.x86_64
    unbound-utils-debuginfo-1.16.3-2.amzn2023.0.1.x86_64
    unbound-libs-debuginfo-1.16.3-2.amzn2023.0.1.x86_64
    unbound-libs-1.16.3-2.amzn2023.0.1.x86_64
    python3-unbound-debuginfo-1.16.3-2.amzn2023.0.1.x86_64
    python3-unbound-1.16.3-2.amzn2023.0.1.x86_64
    unbound-1.16.3-2.amzn2023.0.1.x86_64
    unbound-anchor-1.16.3-2.amzn2023.0.1.x86_64
    unbound-anchor-debuginfo-1.16.3-2.amzn2023.0.1.x86_64
    unbound-utils-1.16.3-2.amzn2023.0.1.x86_64
    unbound-devel-1.16.3-2.amzn2023.0.1.x86_64
    unbound-debugsource-1.16.3-2.amzn2023.0.1.x86_64

Vulnerable software versions

Amazon Linux AMI: All versions

unbound: before 1.16.3-2

CPE2.3 External links

http://alas.aws.amazon.com/AL2023/ALAS-2023-078.html


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

3) Resource exhaustion

EUVDB-ID: #VU69407

Risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2022-3204

CWE-ID: CWE-400 - Resource exhaustion

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to application does not properly control consumption of internal resources when processing a malicious delegation with a considerable number of non responsive nameservers. A remote attacker can trigger CPU high usage and perform a denial of service (DoS) attack.

The attack is known as "Non-Responsive Delegation Attack" (NRDelegation Attack).

Mitigation

Update the affected packages:

aarch64:
    unbound-debuginfo-1.16.3-2.amzn2023.0.1.aarch64
    python3-unbound-debuginfo-1.16.3-2.amzn2023.0.1.aarch64
    unbound-utils-debuginfo-1.16.3-2.amzn2023.0.1.aarch64
    unbound-debugsource-1.16.3-2.amzn2023.0.1.aarch64
    unbound-utils-1.16.3-2.amzn2023.0.1.aarch64
    unbound-libs-debuginfo-1.16.3-2.amzn2023.0.1.aarch64
    unbound-libs-1.16.3-2.amzn2023.0.1.aarch64
    unbound-anchor-1.16.3-2.amzn2023.0.1.aarch64
    python3-unbound-1.16.3-2.amzn2023.0.1.aarch64
    unbound-anchor-debuginfo-1.16.3-2.amzn2023.0.1.aarch64
    unbound-devel-1.16.3-2.amzn2023.0.1.aarch64
    unbound-1.16.3-2.amzn2023.0.1.aarch64

src:
    unbound-1.16.3-2.amzn2023.0.1.src

x86_64:
    unbound-debuginfo-1.16.3-2.amzn2023.0.1.x86_64
    unbound-utils-debuginfo-1.16.3-2.amzn2023.0.1.x86_64
    unbound-libs-debuginfo-1.16.3-2.amzn2023.0.1.x86_64
    unbound-libs-1.16.3-2.amzn2023.0.1.x86_64
    python3-unbound-debuginfo-1.16.3-2.amzn2023.0.1.x86_64
    python3-unbound-1.16.3-2.amzn2023.0.1.x86_64
    unbound-1.16.3-2.amzn2023.0.1.x86_64
    unbound-anchor-1.16.3-2.amzn2023.0.1.x86_64
    unbound-anchor-debuginfo-1.16.3-2.amzn2023.0.1.x86_64
    unbound-utils-1.16.3-2.amzn2023.0.1.x86_64
    unbound-devel-1.16.3-2.amzn2023.0.1.x86_64
    unbound-debugsource-1.16.3-2.amzn2023.0.1.x86_64

Vulnerable software versions

Amazon Linux AMI: All versions

unbound: before 1.16.3-2

CPE2.3 External links

http://alas.aws.amazon.com/AL2023/ALAS-2023-078.html


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.



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