Cisco IOS: Missing Release of Resource after Effective Lifetime
CVE-2022-20697 is a high-severity missing release of resource after effective lifetime vulnerability in Cisco IOS from Cisco, with a CVSS 3.1 base score of 8.6 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 1.16% 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 Cisco IOS 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.
- 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 |
|---|---|---|---|
| Cisco | Cisco IOS | Not specified in the record | Not stated |
| Cisco | iOS | 15.1\(3\)svr1; 15.1\(3\)svr2; 15.1\(3\)svr3; 15.1\(3\)svs; 15.1\(3\)svs1; 15.1\(3\)svt1; 15.1\(3\)svt2; 15.1\(3\)svt3; and 18 more ranges | Not stated |
| Cisco | iOS Xe | 3.11.3ae; 3.11.3e; 3.11.4e | 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
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- 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:C/C:N/I:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.6 | High | CNA (cisco.com) |
| CVSS 3.1 | 8.6 | High | NVD |
| CVSS 2.0 | 6.8 | Medium | NVD |
Official description
A vulnerability in the web services interface of Cisco IOS Software and Cisco IOS XE Software could allow an authenticated, remote attacker to cause a denial of service (DoS) condition. This vulnerability is due to improper resource management in the HTTP server code. An attacker could exploit this vulnerability by sending a large number of HTTP requests to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Missing Release of Resource after Effective Lifetime
The product does not release a resource after its effective lifetime has ended, i.e., after the resource is no longer needed.
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, languages such as Java, Ruby, and Lisp perform automatic garbage collection that releases memory for objects that have been deallocated.
- It is good practice to be responsible for freeing all resources you allocate and to be consistent with how and where you free resources in a function. If you allocate resources that you intend to free upon completion of the function, you must be sure to free the resources at all exit points for that function including error conditions.
More Missing Release of Resource after Effective Lifetime vulnerabilities (CWE-772)
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
Other vulnerabilities in Cisco IOS
- 7.5 High severity
- 8.8 High severity
- 7.7 High severity
- 7.5 High severity
- 7.5 High severity
- 7.2 High severity
Recent Missing Release of Resource after Effective Lifetime vulnerabilities
- 7.5 High severity
- 7.5 High severity
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