CVE-2015-7824: Infoleak
A padding oracle attack was possible against TLS CBC ciphersuites because if a certain length check on the packet fields failed, a different alert type than one used for message authentication failure would be returned to the sender. This check triggering would leak information about the value of the padding bytes and could be used to perform iterative decryption.
As with most such oracle attacks, the danger depends on the underlying protocol - HTTP servers are particularly vulnerable. The current analysis suggests that to exploit it an attacker would first have to guess several bytes of plaintext, but again this is quite possible in many situations including HTTP.
External references:
http://botan.randombit.net/security.html
Other sources
botan 1.11.x before 1.11.22 makes it easier for remote attackers to decrypt TLS ciphertext data via a padding-oracle attack against TLS CBC ciphersuites.
— MITRE
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2015-7824?
CVE-2015-7824 has a high severity rating due to the potential for a padding oracle attack against TLS CBC ciphersuites.
How do I fix CVE-2015-7824?
To fix CVE-2015-7824, upgrade Botan to version 1.11.22 or later.
What software is affected by CVE-2015-7824?
CVE-2015-7824 affects Botan versions up to and including 1.11.21.
What type of attack is enabled by CVE-2015-7824?
CVE-2015-7824 enables a padding oracle attack against TLS CBC ciphersuites.
How can I determine if my system is vulnerable to CVE-2015-7824?
Check if your system is using Botan version 1.11.21 or earlier to determine vulnerability to CVE-2015-7824.