What is CVE-2023-28961?A medium-severity flaw in Junos, explained.
CVE-2023-28961 is a medium-severity flaw (CVSS 5.3) in Junos from Juniper, published on 17 April 2023. It is not on the list of flaws known to be exploited today. The latest forecast puts its chance of use in the next 30 days at 0.4%. If you run an affected version, plan in the vendor’s fix.
Published 17 April 2023. Record last updated 28 April 2023. We keep this page's data up to date.
What is CVE-2023-28961? In plain terms.
It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can change some data.
An Improper Handling of Unexpected Data Type vulnerability in IPv6 firewall filter processing of Juniper Networks Junos OS on the ACX Series devices will prevent a firewall filter with the term 'from next-header ah' from being properly installed in the packet forwarding engine (PFE). There is no immediate indication of an incomplete firewall filter commit shown at the CLI, which could allow an attacker to send valid packets to or through the device that were explicitly intended to be dropped. An indication that the filter was not installed can be identified with the following logs: fpc0 ACX_DFW_CFG_FAILED: ACX Error (dfw):dnx_dfw_rule_prepare : Config failed: Unsupported Ip-protocol 51 in the filter lo0.0-inet6-i fpc0 ACX_DFW_CFG_FAILED: ACX Error (dfw):dnx_dfw_rule_prepare : Please detach the filter, remove unsupported match and re-attach fpc0 ACX_DFW_CFG_FAILED: ACX Error (dfw):dnx_dfw_process_rule : Status:104 dnx_dfw_rule_prepare failed fpc0 ACX_DFW_CFG_FAILED: ACX Error (dfw):dnx_dfw_process_filter : Status:104 dnx_dfw_process_rule failed fpc0 ACX_DFW_CFG_FAILED: ACX Error (dfw):dnx_dfw_update_filter_in_hw : Status:104 Could not process filter(lo0.0-inet6-i) for rule expansion Unsupported match, action present. fpc0 ACX_DFW_CFG_FAILED: ACX Error (dfw):dnx_dfw_create_hw_instance : Status:104 Could not program dfw(lo0.0-inet6-i) type(IFP_DFLT_INET6_Lo0_FILTER)! [104] fpc0 ACX_DFW_CFG_FAILED: ACX Error (dfw):dnx_dfw_bind_shim : [104] Could not create dfw(lo0.0-inet6-i) type(IFP_DFLT_INET6_Lo0_FILTER) fpc0 ACX_DFW_CFG_FAILED: ACX Error (dfw):dnx_dfw_update_resolve : [100] Failed to bind filter(3) to bind point fpc0 ACX_DFW_CFG_FAILED: ACX Error (dfw):dnx_dfw_change_end : dnx_dfw_update_resolve (resolve type) failed This issue affects Juniper Networks Junos OS on ACX Series: All versions prior to 20.2R3-S7; 20.4 versions prior to 20.4R3-S4; 21.1 versions prior to 21.1R3-S3; 21.2 versions prior to 21.2R3-S4; 21.3 versions prior to 21.3R3; 21.4 versions prior to 21.4R3; 22.1 versions prior to 22.1R2.
What kind of flaw is it?
- CWE-241Improper Handling of Unexpected Data Type
How an attack on it works
Read straight from its severity rating, translated out of the shorthand.
- Where an attacker can beAnywhere on the internet
- How hard it is to pull offEasy: no special conditions
- Login needed firstNo login needed
- Does someone have to clickNo, nobody has to do anything
- What an attacker getsCan change some data
Severity vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Is CVE-2023-28961 being exploited? Not that we know of.
It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 0.4%. That can change at any time, which is why we keep watching.
Timeline
- Published
- Record last updated
CVE-2023-28961 scores 22. Action: Monitor.
We keep the score of every published flaw up to date as the evidence changes. Four things go into the score, and evidence that criminals are actually using it counts most. In order:
- Evidence it is being exploitedBiggest factor
- How severe it isStrong factor
- How widely exposed it isSmaller factor
- Threat activity around itSmaller factor
85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score.
When CVE-2023-28961 matches software you track, it lands in your list with its score and the reasons behind it.
See your own ranked list →Who is affected by CVE-2023-28961? 20 products.
The published record lists 20 products from 1 vendor. Versions are shown as published: "before 20.2" means every version up to, but not including, 20.2. If you run one of these, check your version, then go to the fix below.
- Operating system
Junos
by Juniper
Affected versionsbefore 20.220.220.2-r120.2-r1-s120.2-r1-s220.2-r1-s320.2-r220.2-r2-s120.2-r2-s220.2-r2-s320.2-r320.2-r3-s120.2-r3-s220.2-r3-s3 - Hardware
Acx1000
by Juniper
Affected versionsversion not specified - Hardware
Acx1100
by Juniper
Affected versionsversion not specified - Hardware
Acx2000
by Juniper
Affected versionsversion not specified - Hardware
Acx2100
by Juniper
Affected versionsversion not specified - Hardware
Acx2200
by Juniper
Affected versionsversion not specified - Hardware
Acx4000
by Juniper
Affected versionsversion not specified - Hardware
Acx500
by Juniper
Affected versionsversion not specified - Hardware
Acx5000
by Juniper
Affected versionsversion not specified
How do I fix CVE-2023-28961? Four steps.
- Check whether you run itCompare your versions with the affected products above. Not sure what you run? Precursor Intelligence can work it out from your public website, or you can pick it from a list.
- Apply the vendor’s fixInstall the update named in the vendor’s advisory. We’ve put the advisory first in the list.
- If you can’t patch todayFollow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in.
- Keep an eye on itTrack the product and we tell you as soon as we spot this flaw on the list of exploited flaws, or a jump in its exploit likelihood.
References
1 linkDoes CVE-2023-28961 affect you? We'll keep checking.
Looking flaws up one at a time doesn't scale. Tell us what you run once, and we tell you which flaws matter to you, in what order, and keep watching for new ones.
- Tell us what you runPick your software from a list, or let us work it out from your website.
- We match it to every flawOver 400,000 published flaws, checked against your list.
- Ranked by real-world riskA 0 to 100 score, led by evidence criminals are using it.
- Told as soon as we knowAn alert by email, in the app or by webhook to your own tools.
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1 new flaw affects software Acme tracks
An Improper Handling of Unexpected Data Type vulnerability in IPv6 firewall filter processing of Juniper Networks Junos OS on the ACX Series devices will pre...
- Matched to
- Junos on Acme's software list
- What to do
- Plan in the vendor’s update
Sent to the alert recipients Acme chose. Also in the app and to Acme's webhook.
CVE-2023-28961 is a medium-severity flaw in Junos from Juniper, published on 17 April 2023. It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can change some data.
It scores 5.3 out of 10 on the CVSS severity scale, which is medium. Our risk score for CVE-2023-28961 is 22 out of 100, which is Low. Its action is "Monitor". No sign of exploitation and a low forecast. Patch it in your normal update cycle.
It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 0.4%. That can change at any time, which is why we keep watching.
For Junos from Juniper: before 20.2, 20.2, 20.2-r1, 20.2-r1-s1, 20.2-r1-s2, 20.2-r1-s3 and 58 more. The record lists 20 products in all, each with its versions, under "Who is affected" on this page.
Install the update the vendor names in its advisory, linked first under "How do I fix" on this page. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet.