CVE-2002-20001

high-risk
Published 2021-11-11

The Diffie-Hellman Key Agreement Protocol allows remote attackers (from the client side) to send arbitrary numbers that are actually not public keys, and trigger expensive server-side DHE modular-exponentiation calculations, aka a D(HE)at or D(HE)ater attack. The client needs very little CPU resources and network bandwidth. The attack may be more disruptive in cases where a client can require a server to select its largest supported key size. The basic attack scenario is that the client must claim that it can only communicate with DHE, and the server must be configured to allow DHE.

Do I need to act?

!
14.7% chance of exploitation in next 30 days
EPSS score — higher than 85% of all CVEs
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
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Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
7
CVSS 7.5/10 High
NETWORK / LOW complexity

Affected Products (20)

Affected Vendors

Suse Siemens F5 Hpe Stormshield Balasys

References (26)

Third Party Advisory https://cert-portal.siemens.com/productcert/pdf/ssa-506569.pdf
Third Party Advisory https://dheatattack.com
Third Party Advisory https://dheatattack.gitlab.io/
Product https://github.com/Balasys/dheater
Issue Tracking https://github.com/mozilla/ssl-config-generator/issues/162
Third Party Advisory https://gitlab.com/dheatattack/dheater
Technical Description https://ieeexplore.ieee.org/document/10374117
Third Party Advisory https://support.f5.com/csp/article/K83120834
Technical Description https://www.arubanetworks.com/assets/alert/ARUBA-PSA-2022-004.txt
Third Party Advisory https://www.openssl.org/blog/blog/2022/10/21/tls-groups-configuration/
Issue Tracking https://www.reddit.com/r/netsec/comments/qdoosy/server_overload_by_enforcing_dhe...
Exploit https://www.researchgate.net/profile/Anton-Stiglic-2/publication/2401745_Securit...
Third Party Advisory https://www.suse.com/support/kb/doc/?id=000020510
Third Party Advisory https://cert-portal.siemens.com/productcert/pdf/ssa-506569.pdf
Third Party Advisory https://dheatattack.com
Third Party Advisory https://dheatattack.gitlab.io/
Product https://github.com/Balasys/dheater
Issue Tracking https://github.com/mozilla/ssl-config-generator/issues/162
Third Party Advisory https://gitlab.com/dheatattack/dheater
Technical Description https://ieeexplore.ieee.org/document/10374117
and 6 more references
64
/ 100
high-risk
Severity 26/34 · High
Exploitability 12/34 · Low
Exposure 26/34 · High