FreeBSD : Multiple vulnerabilities in Botan (4cd9b19f-f66d-11e5-b94c-001999f8d30b)

Critical Nessus Plugin ID 90287


The remote FreeBSD host is missing a security-related update.


The botan developers reports :

Infinite loop in modular square root algorithm - The ressol function implements the Tonelli-Shanks algorithm for finding square roots could be sent into a nearly infinite loop due to a misplaced conditional check. This could occur if a composite modulus is provided, as this algorithm is only defined for primes. This function is exposed to attacker controlled input via the OS2ECP function during ECC point decompression.

Heap overflow on invalid ECC point - The PointGFp constructor did not check that the affine coordinate arguments were less than the prime, but then in curve multiplication assumed that both arguments if multiplied would fit into an integer twice the size of the prime.

The bigint_mul and bigint_sqr functions received the size of the output buffer, but only used it to dispatch to a faster algorithm in cases where there was sufficient output space to call an unrolled multiplication function.

The result is a heap overflow accessible via ECC point decoding, which accepted untrusted inputs. This is likely exploitable for remote code execution.

On systems which use the mlock pool allocator, it would allow an attacker to overwrite memory held in secure_vector objects. After this point the write will hit the guard page at the end of the mmapped region so it probably could not be used for code execution directly, but would allow overwriting adjacent key material.


Update the affected package.

See Also

Plugin Details

Severity: Critical

ID: 90287

File Name: freebsd_pkg_4cd9b19ff66d11e5b94c001999f8d30b.nasl

Version: $Revision: 2.4 $

Type: local

Published: 2016/04/01

Modified: 2016/10/19

Dependencies: 12634

Risk Information

Risk Factor: Critical


Base Score: 10

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C


Base Score: 9.8

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Vulnerability Information

CPE: p-cpe:/a:freebsd:freebsd:botan110, cpe:/o:freebsd:freebsd

Required KB Items: Host/local_checks_enabled, Host/FreeBSD/release, Host/FreeBSD/pkg_info

Patch Publication Date: 2016/03/31

Vulnerability Publication Date: 2016/02/01

Reference Information

CVE: CVE-2016-2194, CVE-2016-2195