Cisco NX-OS Software: Out-of-bounds Write
CVE-2022-20824 is a high-severity out-of-bounds write vulnerability in Cisco NX-OS Software from Cisco, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 0.4% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Cisco NX-OS Software you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on tools.cisco.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Cisco | Cisco NX-OS Software | Not specified in the record | Not stated |
| Cisco | Mds 9506 Firmware | Not specified in the record | Not stated |
| Cisco | Mds 9513 Firmware | Not specified in the record | Not stated |
| Cisco | Mds 9706 Firmware | Not specified in the record | Not stated |
| Cisco | Mds 9710 Firmware | Not specified in the record | Not stated |
| Cisco | Mds 9718 Firmware | Not specified in the record | Not stated |
| Cisco | Nexus 1000v Firmware | Not specified in the record | Not stated |
| Cisco | Nexus 3016 Firmware | Not specified in the record | Not stated |
| Cisco | Nexus 3016q Firmware | Not specified in the record | Not stated |
| Cisco | Nexus 3048 Firmware | Not specified in the record | Not stated |
| Cisco | Nexus 3064 Firmware | Not specified in the record | Not stated |
| Cisco | Nexus 3064-32t Firmware | Not specified in the record | Not stated |
| Cisco | Nexus 3064-t Firmware | Not specified in the record | Not stated |
| Cisco | Nexus 3064-x Firmware | Not specified in the record | Not stated |
| Cisco | Nexus 3064t Firmware | Not specified in the record | Not stated |
| Cisco | Nexus 3064x Firmware | Not specified in the record | Not stated |
| Cisco | Nexus 3100 Firmware | Not specified in the record | Not stated |
| Cisco | Nexus 3100-v Firmware | Not specified in the record | Not stated |
| Cisco | Nexus 3100-z Firmware | Not specified in the record | Not stated |
| Cisco | Nexus 3100v Firmware | Not specified in the record | Not stated |
| Cisco | Nexus 31108pc-v Firmware | Not specified in the record | Not stated |
| Cisco | Nexus 31108pv-v Firmware | Not specified in the record | Not stated |
| Cisco | Nexus 31108tc-v Firmware | Not specified in the record | Not stated |
| Cisco | Nexus 31128pq Firmware | Not specified in the record | Not stated |
| Cisco | Nexus 3132c-z Firmware | Not specified in the record | Not stated |
Version data comes from the organisation that assigned the CVE; 35 further products are omitted here. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- AdjacentThe attacker must be on the same local network segment.
- 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
- 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:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.8 | High | CNA (cisco.com) |
| CVSS 3.1 | 8.8 | High | NVD |
Official description
A vulnerability in the Cisco Discovery Protocol feature of Cisco FXOS Software and Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to execute arbitrary code with root privileges or cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper input validation of specific values that are within a Cisco Discovery Protocol message. An attacker could exploit this vulnerability by sending a malicious Cisco Discovery Protocol packet to an affected device. A successful exploit could allow the attacker to execute arbitrary code with root privileges or cause the Cisco Discovery Protocol process to crash and restart multiple times, which would cause the affected device to reload, resulting in a DoS condition. Note: Cisco Discovery Protocol is a Layer 2 protocol. To exploit this vulnerability, an attacker must be in the same broadcast domain as the affected device (Layer 2 adjacent).
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Out-of-bounds Write
The product writes data past the end, or before the beginning, of the intended 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.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Third-party and government advisories
- security.netapp.com/advisory/ntap-20220923-0001/Third Party Advisory
Other vulnerabilities in Cisco NX-OS Software
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
Recent Out-of-bounds Write vulnerabilities
- 7.8 High severity
- 9.8 Critical severity
- 7.8 High severity
- 7.8 High severity
Apple iOS and macOS Out-of-Bounds Write Exploited
- 8.8 High severity
Apple iOS and macOS Out-of-Bounds Write Exploited
- 7.8 High severity
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