Security Bulletin: ISC BIND on IBM i is vulnerable to denial of service due to memory leaks and a flaw in resolver code (CVE-2022-2795, CVE-2022-38177, CVE-2022-38178)

Summary

ISC BIND on IBM i is vulnerable to a denial of service attack due to memory leaks in the DNSSEC verification code and a flaw in resolver code to degrade performance as described in the vulnerability details section. IBM i has addressed the vulnerabilities in ISC BIND with a fix as described in the remediation/fixes section.

Vulnerability Details

CVEID:CVE-2022-2795
**DESCRIPTION:**ISC BIND is vulnerable to a denial of service, caused by a flaw in resolver code. By flooding the target resolver with queries, a remote attacker could exploit this vulnerability to severely degrade the resolver’s performance, effectively denying legitimate clients access to the DNS resolution service.
CVSS Base score: 5.3
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/236701 for the current score.
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L)

CVEID:CVE-2022-38177
**DESCRIPTION:**ISC BIND is vulnerable to a denial of service, caused by a small memory leak in the DNSSEC verification code for the ECDSA algorithm. By spoofing the target resolver with responses that have a malformed ECDSA signature, a remote attacker could exploit this vulnerability to cause named to crash.
CVSS Base score: 7.5
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/236705 for the current score.
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

CVEID:CVE-2022-38178
**DESCRIPTION:**ISC BIND is vulnerable to a denial of service, caused by a memory leak in the DNSSEC verification code for the EdDSA algorithm. By spoofing the target resolver with responses that have a malformed EdDSA signature, a remote attacker could exploit this vulnerability to cause named to crash.
CVSS Base score: 7.5
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/236706 for the current score.
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

Affected Products and Versions

Remediation/Fixes

The issue can be fixed by applying PTFs to IBM i. IBM i releases 7.5, 7.4, 7.3, and 7.2 will be fixed.

The IBM i PTF numbers contain the fix for the vulnerabilities.

IBM i Release| 5770-SS1
PTF Number| PTF Download Link
—|—|—
7.5| SI81706| SI81706
7.4| SI81707| SI81707
7.3| SI81708| SI81708
7.2| SI81709| SI81709

<https://www.ibm.com/support/fixcentral&gt;

Important note: IBM recommends that all users running unsupported versions of affected products upgrade to supported and fixed version of affected products.

Workarounds and Mitigations

None