Junos OS: Use After Free
CVE-2022-22207 is a high-severity use after free vulnerability in Junos OS from Juniper Networks, 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. The record lists versions 20.1*, 20.2R3-S5, 20.3R3-S4 as the first without the flaw, so updating Junos OS to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.78% chance of exploitation within 30 days, higher than 57% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Junos OS to 20.1* or 20.2R3-S5 or 20.3R3-S4 or 20.4R3, whichever matches your release line, or a later version.
- Read the advisory on kb.juniper.net 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 |
|---|---|---|---|
| Juniper Networks | Junos OS | 20.1R1 up to, but not including, 20.1*; 20.2 up to, but not including, 20.2R3-S5; 20.3 up to, but not including, 20.3R3-S4; 20.4 up to, but not including, 20.4R3; 21.1 up to, but not including, 21.1R2; 21.2 up to, but not including, 21.2R2 | 20.1*, 20.2R3-S5, 20.3R3-S4, 20.4R3, 21.1R2, 21.2R2 |
| Juniper Networks | Junos | 20.1; 20.2; 20.3; 20.4; 21.1; 21.2 | 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 (juniper.net) |
| CVSS 3.1 | 7.5 | High | NVD |
Official description
A Use After Free vulnerability in the Advanced Forwarding Toolkit (AFT) manager process (aftmand) of Juniper Networks Junos OS allows an unauthenticated networked attacker to cause a kernel crash due to intensive polling of Abstracted Fabric (AF) interface statistics and thereby a Denial of Service (DoS). Continued gathering of AF interface statistics will create a sustained Denial of Service (DoS) condition. This issue affects Juniper Networks Junos OS on MX Series: 20.1 versions later than 20.1R1; 20.2 versions prior to 20.2R3-S5; 20.3 versions prior to 20.3R3-S4; 20.4 versions prior to 20.4R3; 21.1 versions prior to 21.1R2; 21.2 versions prior to 21.2R2.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in Junos OS
- 7.5 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 8.8 High severity
- 8.8 High severity
- 7.5 High severity
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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