RIOT: Buffer Copy without Checking Size of Input
CVE-2024-32017 is a critical-severity buffer copy without checking size of input vulnerability in RIOT from Riot-os, with a CVSS 3.1 base score of 9.0 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected RIOT versions: <= 2023.10; 2023.10 and earlier. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.55% chance of exploitation within 30 days, higher than 76% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of RIOT 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
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
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- NoneNo account or login is needed.
- 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:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 9.8 | Critical | CNA (github.com) |
| CVSS 3.1 | 9.0 | Critical | NVD |
Official description
RIOT is a real-time multi-threading operating system that supports a range of devices that are typically 8-bit, 16-bit and 32-bit microcontrollers. The size check in the `gcoap_dns_server_proxy_get()` function contains a small typo that may lead to a buffer overflow in the subsequent `strcpy()`. In detail, the length of the `_uri` string is checked instead of the length of the `_proxy` string. The `_gcoap_forward_proxy_copy_options()` function does not implement an explicit size check before copying data to the `cep->req_etag` buffer that is `COAP_ETAG_LENGTH_MAX` bytes long. If an attacker can craft input so that `optlen` becomes larger than `COAP_ETAG_LENGTH_MAX`, they can cause a buffer overflow. If the input above is attacker-controlled and crosses a security boundary, the impact of the buffer overflow vulnerabilities could range from denial of service to arbitrary code execution. This issue has yet to be patched. Users are advised to add manual bounds checking.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Buffer Copy without Checking Size of Input
The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.
How developers prevent this class of flaw
- Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
- Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.
More Buffer Copy without Checking Size of Input vulnerabilities (CWE-120)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Third-party and government advisories
- seclists.org/fulldisclosure/2024/May/7Mailing List, Third Party Advisory
- openwall.com/lists/oss-security/2024/05/07/3Mailing List, Third Party Advisory
Other references
Other vulnerabilities in RIOT
- 9.8 Critical severity
- 9.6 Critical severity
- 9.1 Critical severity
- 7.5 High severity
- 8.2 High severity
- 7.1 High severity
Recent Buffer Copy without Checking Size of Input vulnerabilities
- 7.5 High severity
- 7.8 High severity
- 9.0 Critical severity
- 9.0 Critical severity
- 7.8 High severity
- 7.8 High severity
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