grpc-swift: Reachable Assertion
CVE-2022-24777 is a high-severity reachable assertion vulnerability in grpc-swift from Grpc, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected grpc-swift versions: < 1.7.2. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.18% chance of exploitation within 30 days, higher than 68% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of grpc-swift you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Grpc | grpc-swift | < 1.7.2 | Not stated |
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
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | CNA (github.com) |
| CVSS 3.1 | 7.5 | High | NVD |
| CVSS 2.0 | 5.0 | Medium | NVD |
Official description
grpc-swift is the Swift language implementation of gRPC, a remote procedure call (RPC) framework. Prior to version 1.7.2, a grpc-swift server is vulnerable to a denial of service attack via a reachable assertion. This is due to incorrect logic when handling GOAWAY frames. The attack is low-effort: it takes very little resources to construct and send the required sequence of frames. The impact on availability is high as the server will crash, dropping all in flight connections and requests. This issue is fixed in version 1.7.2. There are currently no known workarounds.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Reachable Assertion
The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.
How developers prevent this class of flaw
- If the assertion statement is required (e.g., for security or reliability), change the invoking code to avoid the conditions that trigger the assertion.
- Consider changing the assertion to some other less fatal error. This might not be easy to implement, since other code may be needed to handle the error.
- Make sensitive open/close operations non-reachable from directly user-controlled data (e.g. open/close resources)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- github.com/grpc/grpc-swift/security/advisories/GHSA-r6ww-5963-7r95Third Party Advisory
Patches and release notes
- github.com/grpc/grpc-swift/commit/858f977f2a51fca2292f384cf7a108dc2e73a3bdThird Party Advisory
Recent Reachable Assertion vulnerabilities
- 7.5 High severity
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