Junos OS Evolved: Missing Release of Resource after Effective Lifetime
CVE-2024-39562 is a high-severity missing release of resource after effective lifetime vulnerability in Junos OS Evolved 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 21.4R3-S7-EVO, 22.3R2-S2-EVO, 22.3R3-S2-EVO, 22.4R3-EVO as the first without the flaw, so updating Junos OS Evolved to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.43% 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
- Update Junos OS Evolved to 21.4R3-S7-EVO or 22.3R2-S2-EVO, 22.3R3-S2-EVO or 22.4R3-EVO or 23.2R2-EVO, whichever matches your release line, or a later version.
- Read the advisory on supportportal.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 Evolved | before 21.4R3-S7-EVO; 22.3-EVO up to, but not including, 22.3R2-S2-EVO, 22.3R3-S2-EVO; 22.4-EVO up to, but not including, 22.4R3-EVO; 23.2-EVO up to, but not including, 23.2R2-EVO; before 21.4r3-s7; 22.3 up to, but not including, 22.3r2-s2; 22.3 up to, but not including, 22.3r3-s2; 22.4 up to, but not including, 22.4r3; and 1 more ranges | 21.4R3-S7-EVO, 22.3R2-S2-EVO, 22.3R3-S2-EVO, 22.4R3-EVO, 23.2R2-EVO, 21.4r3-s7, 22.3r2-s2 |
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 CNA (juniper.net).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.7 | High | CNA (juniper.net) |
| CVSS 3.1 | 7.5 | High | CNA (juniper.net) |
Official description
A Missing Release of Resource after Effective Lifetime vulnerability the xinetd process, responsible for spawning SSH daemon (sshd) instances, of Juniper Networks Junos OS Evolved allows an unauthenticated network-based attacker to cause a Denial of Service (DoS) by blocking SSH access for legitimate users. Continued receipt of these connections will create a sustained Denial of Service (DoS) condition. The issue is triggered when a high rate of concurrent SSH requests are received and terminated in a specific way, causing xinetd to crash, and leaving defunct sshd processes. Successful exploitation of this vulnerability blocks both SSH access as well as services which rely upon SSH, such as SFTP, and Netconf over SSH. Once the system is in this state, legitimate users will be unable to SSH to the device until service is manually restored. See WORKAROUND section below. Administrators can monitor an increase in defunct sshd processes by utilizing the CLI command: > show system processes | match sshd root 25219 30901 0 Jul16 ? 00:00:00 [sshd] <defunct> This issue affects Juniper Networks Junos OS Evolved: * All versions prior to 21.4R3-S7-EVO * 22.3-EVO versions prior to 22.3R2-S2-EVO, 22.3R3-S2-EVO; * 22.4-EVO versions prior to 22.4R3-EVO; * 23.2-EVO versions prior to 23.2R2-EVO. This issue does not affect Juniper Networks Junos OS Evolved 22.1-EVO nor 22.2-EVO.
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
Advisories
Other references
Other vulnerabilities in Junos OS Evolved
- 9.8 Critical severity
- 9.8 Critical severity
- 8.8 High severity
- 8.8 High severity
- 7.5 High severity
- 7.5 High severity
Recent Missing Release of Resource after Effective Lifetime vulnerabilities
- 8.6 High severity
- 7.5 High severity
- 8.6 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
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