Junos OS: Improper Check for Unusual or Exceptional Conditions
CVE-2022-22180 is a high-severity improper check for unusual or exceptional conditions 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 18.4R2-S10, 18.4R3-S10, 19.1R3-S7, 19.2R1-S8, 19.2R3-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 0.96% chance of exploitation within 30 days, higher than 62% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Junos OS to 18.4R2-S10, 18.4R3-S10 or 19.1R3-S7 or 19.2R1-S8, 19.2R3-S4 or 19.3R3-S5, 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 | 18.4 up to, but not including, 18.4R2-S10, 18.4R3-S10; 19.1 up to, but not including, 19.1R3-S7; 19.2 up to, but not including, 19.2R1-S8, 19.2R3-S4; 19.3 up to, but not including, 19.3R3-S5; 19.4 up to, but not including, 19.4R3-S7; 20.1 up to, but not including, 20.1R3-S3; 20.2 up to, but not including, 20.2R3-S3; 20.3 up to, but not including, 20.3R3-S2; and 4 more ranges | 18.4R2-S10, 18.4R3-S10, 19.1R3-S7, 19.2R1-S8, 19.2R3-S4, 19.3R3-S5, 19.4R3-S7, 20.1R3-S3 |
| Juniper Networks | Junos | 18.4; 19.1; 19.2; 19.3; 19.4; 20.1; 20.2; 20.3; and 4 more ranges | 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 |
| CVSS 2.0 | 5.0 | Medium | NVD |
Official description
An Improper Check for Unusual or Exceptional Conditions vulnerability in the processing of specific IPv6 packets on certain EX Series devices may lead to exhaustion of DMA memory causing a Denial of Service (DoS). Over time, exploitation of this vulnerability may cause traffic to stop being forwarded, or a crash of the fxpc process. An indication of the issue occurring may be observed through the following log messages: Sep 13 17:14:59 hostname : %PFE-3: fpc0 (buf alloc) failed allocating packet buffer Sep 13 17:14:59 hostname : %PFE-7: fpc0 brcm_pkt_buf_alloc:393 (buf alloc) failed allocating packet buffer When Packet DMA heap utilization reaches 99%, the system will become unstable. Packet DMA heap utilization can be monitored using the command: user@junos# request pfe execute target fpc0 timeout 30 command "show heap" ID Base Total(b) Free(b) Used(b) % Name -- ---------- ----------- ----------- ----------- --- ----------- 0 213301a8 536870488 387228840 149641648 27 Kernel 1 91800000 8388608 3735120 4653488 55 DMA 2 92000000 75497472 74452192 1045280 1 PKT DMA DESC 3 d330000 335544320 257091400 78452920 23 Bcm_sdk 4 96800000 184549376 2408 184546968 99 Packet DMA <<<< 5 903fffe0 20971504 20971504 0 0 Blob This issue affects: Juniper Networks Junos OS 18.4 versions prior to 18.4R2-S10, 18.4R3-S10 on EX2300 Series, EX2300-MP Series, EX3400 Series; 19.1 versions prior to 19.1R3-S7 on EX2300 Series, EX2300-MP Series, EX3400 Series; 19.2 versions prior to 19.2R1-S8, 19.2R3-S4 on EX2300 Series, EX2300-MP Series, EX3400 Series; 19.3 versions prior to 19.3R3-S5 on EX2300 Series, EX2300-MP Series, EX3400 Series; 19.4 versions prior to 19.4R3-S7 on EX2300 Series, EX2300-MP Series, EX3400 Series; 20.1 versions prior to 20.1R3-S3 on EX2300 Series, EX2300-MP Series, EX3400 Series; 20.2 versions prior to 20.2R3-S3 on EX2300 Series, EX2300-MP Series, EX3400 Series; 20.3 versions prior to 20.3R3-S2 on EX2300 Series, EX2300-MP Series, EX3400 Series; 20.4 versions prior to 20.4R3-S1 on EX2300 Series, EX2300-MP Series, EX3400 Series; 21.1 versions prior to 21.1R2-S2, 21.1R3 on EX2300 Series, EX2300-MP Series, EX3400 Series; 21.2 versions prior to 21.2R1-S2, 21.2R2 on EX2300 Series, EX2300-MP Series, EX3400 Series; 21.3 versions prior to 21.3R1-S1, 21.3R2 on EX2300 Series, EX2300-MP Series, EX3400 Series.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Check for Unusual or Exceptional Conditions
The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.
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. Choose languages with features such as exception handling that force the programmer to anticipate unusual conditions that may generate exceptions. Custom exceptions may need to be developed to handle unusual business-logic conditions. Be careful not to pass sensitive exceptions back to the user (CWE-209, CWE-248).
- Check the results of all functions that return a value and verify that the value is expected.
- If using exception handling, catch and throw specific exceptions instead of overly-general exceptions (CWE-396, CWE-397). Catch and handle exceptions as locally as possible so that exceptions do not propagate too far up the call stack (CWE-705). Avoid unchecked or uncaught exceptions where feasible (CWE-248).
More Improper Check for Unusual or Exceptional Conditions vulnerabilities (CWE-754)
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 Improper Check for Unusual or Exceptional Conditions vulnerabilities
- 7.5 High severity
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