Junos OS Evolved: Incorrect Permission Assignment for Critical Resource
CVE-2022-22248 is a high-severity incorrect permission assignment for critical resource vulnerability in Junos OS Evolved from Juniper Networks, with a CVSS 3.1 base score of 7.3 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, but only if a user takes part, for example by opening a link or file. The record lists versions 20.4R3-S1-EVO, 21.1-EVO*, 21.2R3-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 0.19% 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 20.4R3-S1-EVO or 21.1-EVO* or 21.2R3-EVO or 21.3R2-EVO, whichever matches your release line, or a later version.
- Read the advisory on kb.juniper.net for workarounds and exact fixed builds.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Juniper Networks | Junos OS Evolved | 20.4-EVO up to, but not including, 20.4R3-S1-EVO; 21.1R1-EVO up to, but not including, 21.1-EVO*; 21.2-EVO up to, but not including, 21.2R3-EVO; 21.3-EVO up to, but not including, 21.3R2-EVO | 20.4R3-S1-EVO, 21.1-EVO*, 21.2R3-EVO, 21.3R2-EVO |
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
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- 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:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H. Scored by CNA (juniper.net).
Official description
An Incorrect Permission Assignment vulnerability in shell processing of Juniper Networks Junos OS Evolved allows a low-privileged local user to modify the contents of a configuration file which could cause another user to execute arbitrary commands within the context of the follow-on user's session. If the follow-on user is a high-privileged administrator, the attacker could leverage this vulnerability to take complete control of the target system. While this issue is triggered by a user, other than the attacker, accessing the Junos shell, an attacker simply requires Junos CLI access to exploit this vulnerability. This issue affects Juniper Networks Junos OS Evolved: 20.4-EVO versions prior to 20.4R3-S1-EVO; All versions of 21.1-EVO; 21.2-EVO versions prior to 21.2R3-EVO; 21.3-EVO versions prior to 21.3R2-EVO. This issue does not affect Juniper Networks Junos OS Evolved versions prior to 19.2R1-EVO.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Incorrect Permission Assignment for Critical Resource
The product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors.
How developers prevent this class of flaw
- When using a critical resource such as a configuration file, check to see if the resource has insecure permissions (such as being modifiable by any regular user), and generate an error or even exit the software if there is a possibility that the resource could have been modified by an unauthorized party.
- Divide the software into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully defining distinct user groups, privileges, and/or roles. Map these against data, functionality, and the related resources. Then set the permissions accordingly. This will allow you to maintain more fine-grained control over your resources.
- During program startup, explicitly set the default permissions or umask to the most restrictive setting possible. Also set the appropriate permissions during program installation. This will prevent you from inheriting insecure permissions from any user who installs or runs the program.
More Incorrect Permission Assignment for Critical Resource vulnerabilities (CWE-732)
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
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 Incorrect Permission Assignment for Critical Resource vulnerabilities
- 8.8 High severity
- 8.8 High severity
- 9.9 Critical severity
- 7.1 High severity
- 7.8 High severity
- 8.8 High severity
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