National Vulnerability Database

National Vulnerability Database

National Vulnerability
Database

CVE-2019-1686 Detail

Current Description

A vulnerability in the TCP flags inspection feature for access control lists (ACLs) on Cisco ASR 9000 Series Aggregation Services Routers could allow an unauthenticated, remote attacker to bypass protection offered by a configured ACL on an affected device. The vulnerability is due to incorrect processing of the ACL applied to an interface of an affected device when Cisco Express Forwarding load balancing using the 3-tuple hash algorithm is enabled. An attacker could exploit this vulnerability by sending traffic through an affected device that should otherwise be denied by the configured ACL. An exploit could allow the attacker to bypass protection offered by a configured ACL on the affected device. There are workarounds that address this vulnerability. Affected Cisco IOS XR versions are: Cisco IOS XR Software Release 5.1.1 and later till first fixed. First Fixed Releases: 6.5.2 and later, 6.6.1 and later.

Source:  MITRE
View Analysis Description

Impact

CVSS v3.0 Severity and Metrics:

Base Score: 8.6 HIGH
Vector: AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N (V3.0 legend)
Impact Score: 4.0
Exploitability Score: 3.9


Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Changed
Confidentiality (C): None
Integrity (I): High
Availability (A): None

CVSS v2.0 Severity and Metrics:

Base Score: 5.0 MEDIUM
Vector: (AV:N/AC:L/Au:N/C:N/I:P/A:N) (V2 legend)
Impact Subscore: 2.9
Exploitability Subscore: 10.0


Access Vector (AV): Network
Access Complexity (AC): Low
Authentication (AU): None
Confidentiality (C): None
Integrity (I): Partial
Availability (A): None
Additional Information:
Allows unauthorized modification

References to Advisories, Solutions, and Tools

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Hyperlink Resource
http://www.securityfocus.com/bid/108026 Third Party Advisory VDB Entry
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190417-iosxracl Vendor Advisory

Technical Details

Vulnerability Type (View All)

  • Improper Access Control (CWE-284)

Known Affected Software Configurations Switch to CPE 2.2

Configuration 1 ( hide )
 cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:*
     Show Matching CPE(s)
From (including)
5.1.1
Up to (excluding)
6.5.2
 cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:*
     Show Matching CPE(s)
From (including)
6.5.3
Up to (excluding)
6.6.1
Running on/with
 cpe:2.3:h:cisco:asr_9000:-:*:*:*:*:*:*:*
     Show Matching CPE(s)


Change History

4 change records found - show changes

Quick Info

CVE Dictionary Entry:
CVE-2019-1686
NVD Published Date:
04/17/2019
NVD Last Modified:
10/09/2019