Background exploitation KEV catalog No authentication

CVE-2017-12319

Cisco IOS XE Software Ethernet Virtual Private Network Border Gateway Protocol Denial-of-Service Vulnerability

CheckOps priority index

4.3/10 Patch within 7 days

Severity5.9

Probability0.5

Exploitation3/5

Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.

EPSS · today 5.2% higher than 92.5% of CVEs

CVSS 3.1 5.9 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:

Exploited for 1,706 days 03 Mar 2022

CISA due date 24 Mar 2022 for US federal agencies

Exploitation probability EPSS · FIRST

EPSS probability (%)Percentile among all CVEs

Exploitation signals 3 / 5

KEV catalog (CISA)03 Mar 2022
Exploited in EUVD (ENISA)03 Mar 2022
Used by ransomwareno
EPSS above 10 %5.2%
No account, over the networkyes

What to do

Fix

Apply the vendor’s fix as soon as it is available.

CISA guidance: Apply updates per vendor instructions.

Meanwhile

Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.

Manufacturers (CRA)

Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained

Description ENISA EUVD

A vulnerability in the Border Gateway Protocol (BGP) over an Ethernet Virtual Private Network (EVPN) for Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause the device to reload, resulting in a denial of service (DoS) condition, or potentially corrupt the BGP routing table, which could result in network instability. The vulnerability exists due to changes in the implementation of the BGP MPLS-Based Ethernet VPN RFC (RFC 7432) draft between IOS XE software releases. When the BGP Inclusive Multicast Ethernet Tag Route or BGP EVPN MAC/IP Advertisement Route update packet is received, it could be possible that the IP address length field is miscalculated. An attacker could exploit this vulnerability by sending a crafted BGP packet to an affected device after the BGP session was established. An exploit could allow the attacker to cause the affected device to reload or corrupt the BGP routing table; either outcome would result in a DoS. The vulnerability may be triggered when the router receives a crafted BGP message from a peer on an existing BGP session. This vulnerability affects all releases of Cisco IOS XE Software prior to software release 16.3 that support BGP EVPN configurations. If the device is not configured for EVPN, it is not vulnerable. Cisco Bug IDs: CSCui67191, CSCvg52875.

Affected products

Cisco IOS XEIOS XE Software

Affected versions

Cisco IOS XE

Weaknesses (CWE)

CWE-20

Open source packages OSV

Affected libraries according to OSV, with fixed versions.

Timeline

27 Mar 2018
Published
03 Mar 2022
Exploitation reported (ENISA)
03 Mar 2022
Added to the KEV catalog
24 Mar 2022
CISA remediation due date

References

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