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Remote Denial of Service in LwM2M do_write_op_tlv

Moderate
d3zd3z published GHSA-g9mg-fj58-6fqh Apr 26, 2021

Package

zephyr (west)

Affected versions

1.14.2, 2.2.0

Patched versions

2.4.0

Description

Impact

In the Zephyr LwM2M implementation, malformed input can result in an infinite loop, resulting in a denial of service attack.

A remote adversary that can inject LwM2M messages is able to cause a denial of service. The overall risk of this finding is set to Informational because LwM2M is a privileged protocol, which can also implement commands such as reboot or firmware upgrade, and therefore is not expected to be exposed to the internet.

see NCC-ZEP-033

The function do_write_op_tlv, if the TLV entry is not one of the expected types, no processing will be performed. This will result in a loop running forever, resulting in a denial of service.

Patches

This has been fixed in:

For more information

If you have any questions or comments about this advisory:

embargo: 2020-06-25
zepsec: ZEPSEC-56

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVE ID

CVE-2020-13602