CVE Vulnerabilities

CVE-2022-23628

Incorrect Calculation

Published: Feb 09, 2022 | Modified: Feb 17, 2022
CVSS 3.x
5.3
MEDIUM
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
CVSS 2.x
4.3 MEDIUM
AV:N/AC:M/Au:N/C:N/I:P/A:N
RedHat/V2
RedHat/V3
Ubuntu

OPA is an open source, general-purpose policy engine. Under certain conditions, pretty-printing an abstract syntax tree (AST) that contains synthetic nodes could change the logic of some statements by reordering array literals. Example of policies impacted are those that parse and compare web paths. All of these three conditions have to be met to create an adverse effect: 1. An AST of Rego had to be created programmatically such that it ends up containing terms without a location (such as wildcard variables). 2. The AST had to be pretty-printed using the github.com/open-policy-agent/opa/format package. 3. The result of the pretty-printing had to be parsed and evaluated again via an OPA instance using the bundles, or the Golang packages. If any of these three conditions are not met, you are not affected. Notably, all three would be true if using optimized bundles, i.e. bundles created with opa build -O=1 or higher. In that case, the optimizer would fulfil condition (1.), the result of that would be pretty-printed when writing the bundle to disk, fulfilling (2.). When the bundle was then used, wed satisfy (3.). As a workaround users may disable optimization when creating bundles.

Weakness

The product performs a calculation that generates incorrect or unintended results that are later used in security-critical decisions or resource management.

Affected Software

Name Vendor Start Version End Version
Open_policy_agent Openpolicyagent 0.33.1 *

Potential Mitigations

  • Use languages, libraries, or frameworks that make it easier to handle numbers without unexpected consequences.
  • Examples include safe integer handling packages such as SafeInt (C++) or IntegerLib (C or C++).
  • Use languages, libraries, or frameworks that make it easier to handle numbers without unexpected consequences.
  • Examples include safe integer handling packages such as SafeInt (C++) or IntegerLib (C or C++).

References