Off-by-one in Botan - CVE-2018-9860
Published: April 12, 2018 / Updated: August 3, 2020
Vulnerability identifier: #VU33003
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2018-9860
CWE-ID: CWE-193
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote non-authenticated attacker to perform a denial of service (DoS) attack.
An issue was discovered in Botan 1.11.32 through 2.x before 2.6.0. An off-by-one error when processing malformed TLS-CBC ciphertext could cause the receiving side to include in the HMAC computation exactly 64K bytes of data following the record buffer, aka an over-read. The MAC comparison will subsequently fail and the connection will be closed. This could be used for denial of service. No information leak occurs.
Affected software
Botan
botan (Alpine package)
botan (Alpine package)
How to mitigate CVE-2018-9860
Install update from vendor's website.
Botan - update to 2.6.0
botan (Alpine package) - update to 2.7.0-r0
botan (Alpine package) - update to 2.7.0-r0