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Huawei EulerOS: Security Advisory for unbound (EulerOS-SA-2021-2172)
Information
Severity
Severity
Family
Family
CVSSv2 Base
CVSSv2 Base
CVSSv2 Vector
CVSSv2 Vector
Solution Type
Solution Type
Created
Created
Modified
Modified
Summary
The remote host is missing an update for the Huawei EulerOS 'unbound' package(s) announced via the EulerOS-SA-2021-2172 advisory.
Insight
Insight
NLnet Labs Unbound, up to and including version 1.12.0, and NLnet Labs NSD, up to and including version 4.3.3, contain a local vulnerability that would allow for a local symlink attack. When writing the PID file, Unbound and NSD create the file if it is not there, or open an existing file for writing. In case the file was already present, they would follow symlinks if the file happened to be a symlink instead of a regular file. An additional chown of the file would then take place after it was written, making the user Unbound/NSD is supposed to run as the new owner of the file. If an attacker has local access to the user Unbound/NSD runs as, she could create a symlink in place of the PID file pointing to a file that she would like to erase. If then Unbound/NSD is killed and the PID file is not cleared, upon restarting with root privileges, Unbound/NSD will rewrite any file pointed at by the symlink. This is a local vulnerability that could create a Denial of Service of the system Unbound/NSD is running on. It requires an attacker having access to the limited permission user Unbound/NSD runs as and point through the symlink to a critical file on the system.(CVE-2020-28935) Unbound before 1.10.1 has Insufficient Control of Network Message Volume, aka an 'NXNSAttack' issue. This is triggered by random subdomains in the NSDNAME in NS records.(CVE-2020-12662) Unbound before 1.10.1 has an infinite loop via malformed DNS answers received from upstream servers.(CVE-2020-12663)
Affected Software
Affected Software
'unbound' package(s) on Huawei EulerOS Virtualization 3.0.2.2.
Detection Method
Detection Method
Checks if a vulnerable package version is present on the target host.
Solution
Solution
Please install the updated package(s).