CVE-2024-20327: ios xr Input Validation Flaw — Fix

Description

A vulnerability in the PPP over Ethernet (PPPoE) termination feature of Cisco IOS XR Software for Cisco ASR 9000 Series Aggregation Services Routers could allow an unauthenticated, adjacent attacker to crash the ppp_ma process, resulting in a denial of service (DoS) condition. This vulnerability is due to the improper handling of malformed PPPoE packets that are received on a router that is running Broadband Network Gateway (BNG) functionality with PPPoE termination on a Lightspeed-based or Lightspeed-Plus-based line card. An attacker could exploit this vulnerability by sending a crafted PPPoE packet to an affected line card interface that does not terminate PPPoE. A successful exploit could allow the attacker to crash the ppp_ma process, resulting in a DoS condition for PPPoE traffic across the router.

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CVSS v3.1 Score

7.4

HIGH

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Weakness Type (CWE)

CWE-20 Improper Input Validation

Affected Products

Vendor	Product	Versions
cisco	ios_xr	< 7.9.21
cisco	ios_xr	7.10 — 7.10.1
cisco	ios_xr	7.11 — 7.11.1
cisco	asr_9000v-v2	All
cisco	asr_9001	All
cisco	asr_9006	All
cisco	asr_9010	All
cisco	asr_9901	All
cisco	asr_9902	All
cisco	asr_9903	All
cisco	asr_9904	All
cisco	asr_9906	All
cisco	asr_9910	All
cisco	asr_9912	All
cisco	asr_9922	All

References

Advisories & Patches

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-pppma-JKWFgneW https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-pppma-JKWFgneW

Frequently Asked Questions

What is CVE-2024-20327? +

A vulnerability in the PPP over Ethernet (PPPoE) termination feature of Cisco IOS XR Software for Cisco ASR 9000 Series Aggregation Services Routers could allow an unauthenticated, adjacent attacker to crash the ppp_ma process, resulting in a denial of service (DoS) condition. This vulnerability is due to the improper handling of malformed PPPoE packets that are received on a router that is running Broadband Network Gateway (BNG) functionality with PPPoE termination on a Lightspeed-based or Lightspeed-Plus-based line card. An attacker could exploit this vulnerability by sending a crafted PPPoE packet to an affected line card interface that does not terminate PPPoE. A successful exploit could allow the attacker to crash the ppp_ma process, resulting in a DoS condition for PPPoE traffic across the router. It has a CVSS v3.1 base score of 7.4 (HIGH).

How severe is CVE-2024-20327? +

CVE-2024-20327 has a CVSS v3.1 score of 7.4 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2024-20327? +

CVE-2024-20327 affects products from cisco, specifically: asr_9000v-v2, asr_9001, asr_9006, asr_9010, asr_9901, asr_9902, asr_9903, asr_9904, asr_9906, asr_9910, asr_9912, asr_9922, ios_xr. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2024-20327? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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