SynopsisThe remote Samba server is affected by multiple vulnerabilities.
DescriptionThe version of Samba running on the remote host is 4.3.x prior to 4.3.13, 4.4.x prior to 4.4.8, or 4.5.x prior to 4.5.3. It is, therefore, affected by multiple vulnerabilities :
- An overflow condition exists in the ndr_pull_dnsp_name() function in ndr_dnsp.c that is triggered when handling 'dnsRecord' attributes of DNS objects. An authenticated, remote attacker can exploit this, via a specially crafted request, to cause a heap-based buffer overflow, resulting in a denial of service condition or the execution of arbitrary code. (CVE-2016-2123)
- A flaw exists in the client code when performing Kerberos authentication due to always requesting a forwardable Kerberos ticket. An adjacent attacker can exploit this to cause a service accepting the AP-REQ from the client to perform the same actions as the client within the Kerberos TGT, allowing the attacker to impersonate an authenticated user or service.
- A denial of service vulnerability exists in the check_pac_checksum() function in kerberos_pac.c due to improper handling of the arcfour-hmac-md5 PAC (Privilege Attribute Certificate) checksum. An authenticated, remote attacker can exploit this to corrupt memory, resulting in a crash of the winbindd process. (CVE-2016-2126)
Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.
SolutionUpgrade to Samba version 4.3.13 / 4.4.8 / 4.5.3 or later.
Alternatively, apply the vendor-supplied security patch referenced in the advisory.