Vulnerability CVE-2020-15213

Vulnerability Name:

CVE-2020-15213 (CCN-188972)

Assigned:

2020-06-25

Published:

2020-06-25

Updated:

2021-11-18

Summary:

In TensorFlow Lite before versions 2.2.1 and 2.3.1, models using segment sum can trigger a denial of service by causing an out of memory allocation in the implementation of segment sum. Since code uses the last element of the tensor holding them to determine the dimensionality of output tensor, attackers can use a very large value to trigger a large allocation. The issue is patched in commit 204945b19e44b57906c9344c0d00120eeeae178a and is released in TensorFlow versions 2.2.1, or 2.3.1. A potential workaround would be to add a custom `Verifier` to limit the maximum value in the segment ids tensor. This only handles the case when the segment ids are stored statically in the model, but a similar validation could be done if the segment ids are generated at runtime, between inference steps. However, if the segment ids are generated as outputs of a tensor during inference steps, then there are no possible workaround and users are advised to upgrade to patched code.

CVSS v3 Severity:

4.0 Medium (CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:L)
3.5 Low (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:L/E:U/RL:O/RC:C)

Exploitability Metrics:	Attack Vector (AV): Network Attack Complexity (AC): High Privileges Required (PR): None User Interaction (UI): None
Scope:	Scope (S): Changed
Impact Metrics:	Confidentiality (C): None Integrity (I): None Availibility (A): Low

4.0 Medium (CCN CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L)
3.5 Low (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C)

Exploitability Metrics:	Attack Vector (AV): Local Attack Complexity (AC): Low Privileges Required (PR): None User Interaction (UI): None
Scope:	Scope (S): Unchanged
Impact Metrics:	Confidentiality (C): None Integrity (I): None Availibility (A): Low

CVSS v2 Severity:

4.3 Medium (CVSS v2 Vector: AV:N/AC:M/Au:N/C:N/I:N/A:P)

Exploitability Metrics:	Access Vector (AV): Network Access Complexity (AC): Medium Authentication (Au): None
Impact Metrics:	Confidentiality (C): None Integrity (I): None Availibility (A): Partial

2.1 Low (CCN CVSS v2 Vector: AV:L/AC:L/Au:N/C:N/I:N/A:P)

Exploitability Metrics:	Access Vector (AV): Local Access Complexity (AC): Low Athentication (Au): None
Impact Metrics:	Confidentiality (C): None Integrity (I): None Availibility (A): Partial