FS#58198 - [botan] CVE-2018-9860: Memory overread in TLS CBC decryption

Attached to Project: Community Packages
Opened by Karol Babioch (kbabioch) - Wednesday, 11 April 2018, 12:40 GMT
Last edited by Alexander F. Rødseth (xyproto) - Sunday, 15 April 2018, 14:57 GMT
Task Type Bug Report
Category Packages
Status Closed
Assigned To Alexander F. Rødseth (xyproto)
Levente Polyak (anthraxx)
Architecture All
Severity Low
Priority Normal
Reported Version
Due in Version Undecided
Due Date Undecided
Percent Complete 100%
Votes 0
Private No

Details

An off by one error in TLS CBC decryption meant that for a particular malformed ciphertext, the receiver would miscompute a length field and HMAC exactly 64K bytes of data following the record buffer as if it was part of the message. This cannot be used to leak information since the MAC comparison will subsequently fail and the connection will be closed. However it might be used for denial of service. Found by OSS-Fuzz.

Bug introduced in 1.11.32, fixed in 2.6.0

References:
https://github.com/randombit/botan/blob/master/doc/security.rst
This task depends upon

Closed by  Alexander F. Rødseth (xyproto)
Sunday, 15 April 2018, 14:57 GMT
Reason for closing:  Fixed
Comment by Alexander F. Rødseth (xyproto) - Thursday, 12 April 2018, 21:12 GMT
Thanks for reporting, botan 2.6.0 is now in [community-staging].

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