CyberSecBulletin
CVE-2022-46152NVD status: Analyzed

optee_os: Improper Validation of Array Index

Published Updated By the CyberSecBulletin desk

CVE-2022-46152 is a high-severity improper validation of array index vulnerability in optee_os from OP-TEE, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. Affected optee_os versions: < 3.19.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.49% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Op-tee to 3.19.0 or a later version.
  2. Read the advisory on github.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
OP-TEEoptee_os< 3.19.0Not stated
TrustedfirmwareOp-teebefore 3.19.03.19.0

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
ChangedThe attack can reach beyond the vulnerable component into other systems.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.18.2HighCNA (github.com)
CVSS 3.18.8HighNVD

Official description

OP-TEE Trusted OS is the secure side implementation of OP-TEE project, a Trusted Execution Environment. Versions prior to 3.19.0, contain an Improper Validation of Array Index vulnerability. The function `cleanup_shm_refs()` is called by both `entry_invoke_command()` and `entry_open_session()`. The commands `OPTEE_MSG_CMD_OPEN_SESSION` and `OPTEE_MSG_CMD_INVOKE_COMMAND` can be executed from the normal world via an OP-TEE SMC. This function is not validating the `num_params` argument, which is only limited to `OPTEE_MSG_MAX_NUM_PARAMS` (127) in the function `get_cmd_buffer()`. Therefore, an attacker in the normal world can craft an SMC call that will cause out-of-bounds reading in `cleanup_shm_refs` and potentially freeing of fake-objects in the function `mobj_put()`. A normal-world attacker with permission to execute SMC instructions may exploit this flaw. Maintainers believe this problem permits local privilege escalation from the normal world to the secure world. Version 3.19.0 contains a fix for this issue. There are no known workarounds.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Validation of Array Index

The product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array.

How developers prevent this class of flaw

  • Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, Ada allows the programmer to constrain the values of a variable and languages such as Java and Ruby will allow the programmer to handle exceptions when an out-of-bounds index is accessed.
  • Use a CPU and operating system that offers Data Execution Protection (using hardware NX or XD bits) or the equivalent techniques that simulate this feature in software, such as PaX. These techniques ensure that any instruction executed is exclusively at a memory address that is part of the code segment. For more information on these techniques see D3-PSEP (Process Segment Execution Prevention) from D3FEND.

More Improper Validation of Array Index vulnerabilities (CWE-129)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in optee_os

All optee_os vulnerabilities

Recent Improper Validation of Array Index vulnerabilities

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