CyberSecBulletin
CVE-2024-30394NVD status: Analyzed

Junos OS: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2024-30394 is a high-severity out-of-bounds write 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 21.2R3-S7, 21.4R3-S5, 22.1R3-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 0.66% chance of exploitation within 30 days, higher than 52% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Junos OS to 21.2R3-S7 or 21.4R3-S5 or 22.1R3-S4 or 22.2R3-S2, whichever matches your release line, or a later version.
  2. Update Junos OS Evolved to 21.4R3-S5-EVO or 22.1R3-S4-EVO or 22.2R3-S2-EVO or 22.3R3-S1-EVO, whichever matches your release line, or a later version.
  3. Update Junos to 21.2 or a later version.
  4. Read the advisory on supportportal.juniper.net for workarounds and exact fixed builds.
  5. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
Juniper NetworksJunos OSbefore 21.2R3-S7; 21.4 up to, but not including, 21.4R3-S5; 22.1 up to, but not including, 22.1R3-S4; 22.2 up to, but not including, 22.2R3-S2; 22.3 up to, but not including, 22.3R3-S1; 22.4 up to, but not including, 22.4R3; 23.2 up to, but not including, 23.2R221.2R3-S7, 21.4R3-S5, 22.1R3-S4, 22.2R3-S2, 22.3R3-S1, 22.4R3
Juniper NetworksJunos OS Evolvedbefore 21.4R3-S5-EVO; 22.1-EVO up to, but not including, 22.1R3-S4-EVO; 22.2-EVO up to, but not including, 22.2R3-S2-EVO; 22.3-EVO up to, but not including, 22.3R3-S1-EVO; 22.4-EVO up to, but not including, 22.4R3-EVO; 23.2-EVO up to, but not including, 23.2R2-EVO21.4R3-S5-EVO, 22.1R3-S4-EVO, 22.2R3-S2-EVO, 22.3R3-S1-EVO, 22.4R3-EVO, 23.2R2-EVO
Juniper NetworksJunosbefore 21.2; 21.2; 21.4; 22.1; 22.2; 22.3; 22.4; 23.221.2

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 systemScoreSeverityScored by
CVSS 4.08.7HighCNA (juniper.net)
CVSS 3.17.5HighCNA (juniper.net)

Official description

A Stack-based Buffer Overflow vulnerability in the Routing Protocol Daemon (RPD) component of Junos OS and Junos OS Evolved allows an unauthenticated, network-based attacker to cause an rpd crash, leading to Denial of Service (DoS). On all Junos OS and Junos OS Evolved platforms, when EVPN is configured, and a specific EVPN type-5 route is received via BGP, rpd crashes and restarts. Continuous receipt of this specific route will lead to a sustained Denial of Service (DoS) condition. This issue affects: Junos OS: * all versions before 21.2R3-S7, * from 21.4 before 21.4R3-S5, * from 22.1 before 22.1R3-S4, * from 22.2 before 22.2R3-S2, * from 22.3 before 22.3R3-S1, * from 22.4 before 22.4R3, * from 23.2 before 23.2R2. Junos OS Evolved: * all versions before 21.4R3-S5-EVO, * from 22.1-EVO before 22.1R3-S4-EVO, * from 22.2-EVO before 22.2R3-S2-EVO, * from 22.3-EVO before 22.3R3-S1-EVO, * from 22.4-EVO before 22.4R3-EVO, * from 23.2-EVO before 23.2R2-EVO.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Out-of-bounds Write

The product writes data past the end, or before the beginning, of the intended buffer.

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, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.

More Out-of-bounds Write vulnerabilities (CWE-787)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in Junos OS

All Junos OS vulnerabilities

Recent Out-of-bounds Write vulnerabilities

Spotted an error? Tell us.