CVE-2023-20109KEV · OVERDUECWE-787

Cisco IOS and IOS XE Group Encrypted Transport VPN Out-of-Bounds Write Vulnerability

Medium · published September 27, 2023

Patch now

The score understates this — it's already being exploited

CVSS calls it medium at 6.6. It is confirmed in active exploitation. It sits in the 84.5th percentile for exploit probability.

1088
days past CISA
deadline
CVSS v3.1
6.6
EPSS
2%
Percentile
84.5
In the wild
Confirmed
What it is

⚠️ An authenticated attacker can exploit Cisco's Group Encrypted Transport VPN with just a little tweak! Imagine the chaos if someone with admin access decides to play puppet master! 🎭 Think of it like a hotel where a guest (the attacker) can change their room number to redirect all mail to themselves instead of the rightful tenant. If they control the key server, they can open the door to all the sensitive data inside! If successfully exploited, this vulnerability could lead to the attacker executing arbitrary code or, worse, causing the device to crash entirely — akin to a power outage in a busy hotel where everyone is left in the dark! Imagine the disruption to services and potential data loss or theft. It's a situation that could destabilize your entire network!

Put simply

Think of it like a hotel where a guest (the attacker) can change their room number to redirect all mail to themselves instead of the rightful tenant. If they control the key server, they can open the door to all the sensitive data inside! This vulnerability arises from insufficient validation of attributes within the Group Domain of Interpretation (GDOI) and G-IKEv2 protocols in Cisco's GET VPN feature. An attacker can exploit this flaw by compromising a key server or misconfiguring a group member to point to a malicious server.

What to do

If successfully exploited, this vulnerability could lead to the attacker executing arbitrary code or, worse, causing the device to crash entirely — akin to a power outage in a busy hotel where everyone is left in the dark! Imagine the disruption to services and potential data loss or theft. It's a situation that could destabilize your entire network! To mitigate this risk, ensure you update to the latest Cisco IOS Software or Cisco IOS XE Software version that addresses this vulnerability. Additionally, review and secure your VPN configurations to prevent unauthorized access to key servers. It's time to tighten those network defenses! You've got this! Following these steps will help secure your network and keep those digital doors locked tight! 🛡️

The record
Technical detail
CVSS v3.1
6.6 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.02484 · 84.5th percentile
Weakness
CWE-787 · Out-of-bounds Write
Published
2023-09-27T17:23Z
KEV added
2023-10-10 · due 2023-10-31
EPSS history
Timeline
  • 10 OCT 00:00Z
    Added to CISA KEV — remediate by Oct 31
    kev
  • 27 SEP 17:23Z
    A vulnerability in the Cisco Group Encrypted Transport VPN (GET VPN) feature of Cisco IOS Software and Cisco IOS XE Software could allow an authenticated…
    cvelistv5