CVE-2024-20513

MEDIUM
Published Oct 2, 2024 Modified Jun 4, 2025 CWE-639

Description

A vulnerability in the Cisco AnyConnect VPN server of Cisco Meraki MX and Cisco Meraki Z Series Teleworker Gateway devices could allow an unauthenticated, remote attacker to cause a DoS condition for targeted users of the AnyConnect service on an affected device. This vulnerability is due to insufficient entropy for handlers that are used during SSL VPN session establishment. An unauthenticated attacker could exploit this vulnerability by brute forcing valid session handlers. An authenticated attacker could exploit this vulnerability by connecting to the AnyConnect VPN service of an affected device to retrieve a valid session handler and, based on that handler, predict further valid session handlers. The attacker would then send a crafted HTTPS request using the brute-forced or predicted session handler to the AnyConnect VPN server of the device. A successful exploit could allow the attacker to terminate targeted SSL VPN sessions, forcing remote users to initiate new VPN connections and reauthenticate.

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CVSS v3.1 Score

5.8
MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L

Weakness Type (CWE)

CWE-639 CWE-639

Affected Products

Vendor Product
cisco meraki_mx65_firmware
cisco meraki_mx65
cisco meraki_mx64_firmware
cisco meraki_mx64
cisco meraki_z4c_firmware
cisco meraki_z4c
cisco meraki_z4_firmware
cisco meraki_z4
cisco meraki_z3c_firmware
cisco meraki_z3c
cisco meraki_z3_firmware
cisco meraki_z3
cisco meraki_vmx_firmware
cisco meraki_vmx
cisco meraki_mx600_firmware
cisco meraki_mx600
cisco meraki_mx450_firmware
cisco meraki_mx450
cisco meraki_mx400_firmware
cisco meraki_mx400
cisco meraki_mx250_firmware
cisco meraki_mx250
cisco meraki_mx105_firmware
cisco meraki_mx105
cisco meraki_mx100_firmware
cisco meraki_mx100
cisco meraki_mx95_firmware
cisco meraki_mx95
cisco meraki_mx85_firmware
cisco meraki_mx85
cisco meraki_mx84_firmware
cisco meraki_mx84
cisco meraki_mx75_firmware
cisco meraki_mx75
cisco meraki_mx68w_firmware
cisco meraki_mx68w
cisco meraki_mx68cw_firmware
cisco meraki_mx68cw
cisco meraki_mx68_firmware
cisco meraki_mx68
cisco meraki_mx67w_firmware
cisco meraki_mx67w
cisco meraki_mx67c_firmware
cisco meraki_mx67c
cisco meraki_mx67_firmware
cisco meraki_mx67
cisco meraki_mx65w_firmware
cisco meraki_mx65w
cisco meraki_mx64w_firmware
cisco meraki_mx64w

References

Frequently Asked Questions

What is CVE-2024-20513? +
A vulnerability in the Cisco AnyConnect VPN server of Cisco Meraki MX and Cisco Meraki Z Series Teleworker Gateway devices could allow an unauthenticated, remote attacker to cause a DoS condition for targeted users of the AnyConnect service on an affected device. This vulnerability is due to insufficient entropy for handlers that are used during SSL VPN session establishment. An unauthenticated attacker could exploit this vulnerability by brute forcing valid session handlers. An authenticated attacker could exploit this vulnerability by connecting to the AnyConnect VPN service of an affected device to retrieve a valid session handler and, based on that handler, predict further valid session handlers. The attacker would then send a crafted HTTPS request using the brute-forced or predicted session handler to the AnyConnect VPN server of the device. A successful exploit could allow the attacker to terminate targeted SSL VPN sessions, forcing remote users to initiate new VPN connections and reauthenticate. It has a CVSS v3.1 base score of 5.8 (MEDIUM).
How severe is CVE-2024-20513? +
CVE-2024-20513 has a CVSS v3.1 score of 5.8 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.
What products are affected by CVE-2024-20513? +
CVE-2024-20513 affects products from cisco, specifically: meraki_mx100, meraki_mx100_firmware, meraki_mx105, meraki_mx105_firmware, meraki_mx250, meraki_mx250_firmware, meraki_mx400, meraki_mx400_firmware, meraki_mx450, meraki_mx450_firmware, meraki_mx600, meraki_mx600_firmware, meraki_mx64, meraki_mx64_firmware, meraki_mx64w, meraki_mx64w_firmware, meraki_mx65, meraki_mx65_firmware, meraki_mx65w, meraki_mx65w_firmware, meraki_mx67, meraki_mx67_firmware, meraki_mx67c, meraki_mx67c_firmware, meraki_mx67w, meraki_mx67w_firmware, meraki_mx68, meraki_mx68_firmware, meraki_mx68cw, meraki_mx68cw_firmware, meraki_mx68w, meraki_mx68w_firmware, meraki_mx75, meraki_mx75_firmware, meraki_mx84, meraki_mx84_firmware, meraki_mx85, meraki_mx85_firmware, meraki_mx95, meraki_mx95_firmware, meraki_vmx, meraki_vmx_firmware, meraki_z3, meraki_z3_firmware, meraki_z3c, meraki_z3c_firmware, meraki_z4, meraki_z4_firmware, meraki_z4c, meraki_z4c_firmware. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2024-20513? +
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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