CyberSecBulletin
CVE-2023-44197NVD status: Modified

Junos OS: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2023-44197 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 20.4R3-S8, 21.1*, 21.2R3-S2 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 0.62% chance of exploitation within 30 days, higher than 50% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Junos OS to 20.4R3-S8 or 21.1* or 21.2R3-S2 or 21.3R3-S5, whichever matches your release line, or a later version.
  2. Update Junos OS Evolved to 20.4R3-S8-EVO or 21.1*-EVO or 21.2R3-S2-EVO or 21.3*-EVO, whichever matches your release line, or a later version.
  3. Update Junos to 20.4 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 20.4R3-S8; 21.1R1 up to, but not including, 21.1*; 21.2 up to, but not including, 21.2R3-S2; 21.3 up to, but not including, 21.3R3-S5; 21.4 up to, but not including, 21.4R2-S1, 21.4R3-S520.4R3-S8, 21.1*, 21.2R3-S2, 21.3R3-S5, 21.4R2-S1, 21.4R3-S5
Juniper NetworksJunos OS Evolvedbefore 20.4R3-S8-EVO; 21.1R1-EVO up to, but not including, 21.1*-EVO; 21.2-EVO up to, but not including, 21.2R3-S2-EVO; 21.3R1-EVO up to, but not including, 21.3*-EVO; 21.4-EVO up to, but not including, 21.4R2-S1-EVO, 21.4R3-S5-EVO20.4R3-S8-EVO, 21.1*-EVO, 21.2R3-S2-EVO, 21.3*-EVO, 21.4R2-S1-EVO, 21.4R3-S5-EVO
Juniper NetworksJunosbefore 20.4; 20.4; 21.1; 21.2; 21.3; 21.420.4

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

Official description

An Out-of-Bounds Write vulnerability in the Routing Protocol Daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, network-based attacker to cause a Denial of Service (DoS). On all Junos OS and Junos OS Evolved devices an rpd crash and restart can occur while processing BGP route updates received over an established BGP session. This specific issue is observed for BGP routes learned via a peer which is configured with a BGP import policy that has hundreds of terms matching IPv4 and/or IPv6 prefixes. This issue affects Juniper Networks Junos OS: * All versions prior to 20.4R3-S8; * 21.1 version 21.1R1 and later versions; * 21.2 versions prior to 21.2R3-S2; * 21.3 versions prior to 21.3R3-S5; * 21.4 versions prior to 21.4R2-S1, 21.4R3-S5. This issue affects Juniper Networks Junos OS Evolved: * All versions prior to 20.4R3-S8-EVO; * 21.1-EVO version 21.1R1-EVO and later versions; * 21.2-EVO versions prior to 21.2R3-S2-EVO; * 21.3-EVO version 21.3R1-EVO and later versions; * 21.4-EVO versions prior to 21.4R2-S1-EVO, 21.4R3-S5-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

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