2.6 Low
CVSS2
Access Vector
NETWORK
Access Complexity
HIGH
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
NONE
Availability Impact
NONE
AV:N/AC:H/Au:N/C:P/I:N/A:N
0.006 Low
EPSS
Percentile
78.3%
The OpenSSL ladder implementation for scalar multiplication of points on elliptic curves over binary fields is susceptible to a timing attack vulnerability. This vulnerability can be used to steal the private key of a TLS server that authenticates with ECDSA signatures and binary curves.
Billy Bob Brumley’s and Nicola Tuveri’s paper “Remote Timing Attacks are Still Practical” states:
_ "For over two decades, timing attacks have been an active area of research within applied cryptography. These attacks exploit cryptosystem or protocol implementations that do not run in constant time. When implementing an elliptic curve cryptosystem that provides side-channel resistance, the scalar multiplication routine is a critical component. In such instances, one attractive method often suggested in the literature is Montgomery’s ladder that performs a fixed sequence of curve and field operations. _
This paper describes a timing attack vulnerability in OpenSSL’s ladder implementation for curves over binary fields. We use this vulnerability to steal the private key of a TLS server where the server authenticates with ECDSA signatures. Using the timing of the exchanged messages, the messages themselves, and the signatures, we mount a lattice attack that recovers the private key."
A remote attacker can retrieve the private key of a TLS server that authenticates with ECDSA signatures and binary curves.
We are currently unaware of a practical solution to this problem.
Do not use ECDSA signatures and binary curves for authentication.
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Notified: March 29, 2011 Updated: May 11, 2011
Affected
“The OpenSSL team have reviewed the paper, and although the result is significant, we believe that the affected code (ECDSA used with binary curves) is very rarely used at present. We therefore do not plan on issuing a security release but expect to patch this in the future.”
We are not aware of further vendor information regarding this vulnerability.
Notified: April 21, 2011 Updated: April 21, 2011
Unknown
We have not received a statement from the vendor.
We are not aware of further vendor information regarding this vulnerability.
Notified: May 10, 2011 Updated: May 10, 2011
Unknown
We have not received a statement from the vendor.
We are not aware of further vendor information regarding this vulnerability.
Notified: May 10, 2011 Updated: May 10, 2011
Unknown
We have not received a statement from the vendor.
We are not aware of further vendor information regarding this vulnerability.
Notified: May 10, 2011 Updated: May 10, 2011
Unknown
We have not received a statement from the vendor.
We are not aware of further vendor information regarding this vulnerability.
Notified: May 10, 2011 Updated: May 10, 2011
Unknown
We have not received a statement from the vendor.
We are not aware of further vendor information regarding this vulnerability.
Notified: May 10, 2011 Updated: May 10, 2011
Unknown
We have not received a statement from the vendor.
We are not aware of further vendor information regarding this vulnerability.
Notified: May 10, 2011 Updated: May 10, 2011
Unknown
We have not received a statement from the vendor.
We are not aware of further vendor information regarding this vulnerability.
Notified: May 10, 2011 Updated: May 10, 2011
Unknown
We have not received a statement from the vendor.
We are not aware of further vendor information regarding this vulnerability.
Notified: May 10, 2011 Updated: May 10, 2011
Unknown
We have not received a statement from the vendor.
We are not aware of further vendor information regarding this vulnerability.
Notified: May 10, 2011 Updated: May 10, 2011
Unknown
We have not received a statement from the vendor.
We are not aware of further vendor information regarding this vulnerability.
Notified: May 10, 2011 Updated: May 10, 2011
Unknown
We have not received a statement from the vendor.
We are not aware of further vendor information regarding this vulnerability.
Notified: May 10, 2011 Updated: May 10, 2011
Unknown
We have not received a statement from the vendor.
We are not aware of further vendor information regarding this vulnerability.
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Group | Score | Vector |
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Base | ||
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Environmental |
Thanks to Billy Brumley for reporting this vulnerability.
This document was written by Jared Allar.
CVE IDs: | CVE-2011-1945 |
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Severity Metric: | 0.13 Date Public: |