CVE-2018-16841 - Double Free

Severity

40%

Complexity

80%

Confidentiality

48%

Samba from version 4.3.0 and before versions 4.7.12, 4.8.7 and 4.9.3 are vulnerable to a denial of service. When configured to accept smart-card authentication, Samba's KDC will call talloc_free() twice on the same memory if the principal in a validly signed certificate does not match the principal in the AS-REQ. This is only possible after authentication with a trusted certificate. talloc is robust against further corruption from a double-free with talloc_free() and directly calls abort(), terminating the KDC process.

Samba from version 4.3.0 and before versions 4.7.12, 4.8.7 and 4.9.3 are vulnerable to a denial of service. When configured to accept smart-card authentication, Samba's KDC will call talloc_free() twice on the same memory if the principal in a validly signed certificate does not match the principal in the AS-REQ. This is only possible after authentication with a trusted certificate. talloc is robust against further corruption from a double-free with talloc_free() and directly calls abort(), terminating the KDC process.

CVSS 3.0 Base Score 6.5. CVSS Attack Vector: network. CVSS Attack Complexity: low. CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H).

CVSS 2.0 Base Score 4. CVSS Attack Vector: network. CVSS Attack Complexity: low. CVSS Vector: (AV:N/AC:L/Au:S/C:N/I:N/A:P).

Demo Examples

Double Free

CWE-415

Double Free

CWE-415

While contrived, this code should be exploitable on Linux distributions which do not ship with heap-chunk check summing turned on.


               
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free(buf1R2);

Overview

First reported 6 years ago

2018-11-28 14:29:00

Last updated 5 years ago

2019-10-09 23:36:00

Affected Software

Samba Samba

Canonical Ubuntu Linux 12.04 ESM (Extended Security Maintenance)

12.04

Canonical Ubuntu Linux 14.04 LTS (Long-Term Support)

14.04

Canonical Ubuntu Linux 16.04 LTS (Long-Term Support)

16.04

Canonical Ubuntu Linux 18.04 LTS Edition

18.04

Canonical Ubuntu Linux 18.10

18.10

Debian Linux 9.0

9.0

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