CyberSecBulletin
CVE-2022-47631NVD status: Modified

Synapse: Time-of-check Time-of-use (TOCTOU) Race Condition

Published Updated By the CyberSecBulletin desk

CVE-2022-47631 is a high-severity time-of-check time-of-use (TOCTOU) race condition vulnerability in Synapse from Razer, with a CVSS 3.1 base score of 7.8 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. The record lists version 3.8.0428.042117 as the first without the flaw, so updating Synapse to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.39% 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 Synapse to 3.8.0428.042117 or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
RazerSynapsebefore 3.8.0428.0421173.8.0428.042117

Version data comes from NVD's product matching. 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
HighSuccess depends on conditions outside the attacker's control.
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:H/PR:L/UI:N/S:C/C:H/I:H/A:H. Scored by NVD.

Official description

Razer Synapse through 3.7.1209.121307 allows privilege escalation due to an unsafe installation path and improper privilege management. Attackers can place DLLs into %PROGRAMDATA%\Razer\Synapse3\Service\bin if they do so before the service is installed and if they deny write access for the SYSTEM user. Although the service will not start if it detects malicious DLLs in this directory, attackers can exploit a race condition and replace a valid DLL (i.e., a copy of a legitimate Razer DLL) with a malicious DLL after the service has already checked the file. As a result, local Windows users can abuse the Razer driver installer to obtain administrative privileges on Windows.

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

The underlying weakness: Time-of-check Time-of-use (TOCTOU) Race Condition

The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.

How developers prevent this class of flaw

  • The most basic advice for TOCTOU vulnerabilities is to not perform a check before the use. This does not resolve the underlying issue of the execution of a function on a resource whose state and identity cannot be assured, but it does help to limit the false sense of security given by the check.
  • When the file being altered is owned by the current user and group, set the effective gid and uid to that of the current user and group when executing this statement.
  • Limit the interleaving of operations on files from multiple processes.

More Time-of-check Time-of-use (TOCTOU) Race Condition vulnerabilities (CWE-367)

Timeline

  1. CVE record published.
  2. Record last changed materially (score, affected products, status or references).

References

Technical write-ups (may include proof of concept)

Other vulnerabilities in Synapse

All Synapse vulnerabilities

Recent Time-of-check Time-of-use (TOCTOU) Race Condition vulnerabilities

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