CVE-2016-2123

A flaw was found in samba versions 4.0.0 to 4.5.2. The Samba routine ndr_pull_dnsp_name contains an integer wrap problem, leading to an attacker-controlled memory overwrite. ndr_pull_dnsp_name parses data from the Samba Active Directory ldb database. Any user who can write to the dnsRecord attribute over LDAP can trigger this memory corruption. By default, all authenticated LDAP users can write to the dnsRecord attribute on new DNS objects. This makes the defect a remote privilege escalation.

A flaw was found in samba versions 4.0.0 to 4.5.2. The Samba routine ndr_pull_dnsp_name contains an integer wrap problem, leading to an attacker-controlled memory overwrite. ndr_pull_dnsp_name parses data from the Samba Active Directory ldb database. Any user who can write to the dnsRecord attribute over LDAP can trigger this memory corruption. By default, all authenticated LDAP users can write to the dnsRecord attribute on new DNS objects. This makes the defect a remote privilege escalation.

These are all security issues fixed in the ctdb-4.14.6+git.182.2205d5224e3-1.1 package on the GA media of openSUSE Tumbleweed.

This update for samba fixes the following issues:

Security issues fixed:

• CVE-2016-2125: Don't send delegated credentials to all servers. (bsc#1014441).
• CVE-2016-2126: Denial of service due to a client triggered crash in the winbindd parent process. (bsc#1014442).
• CVE-2016-2123: Heap-based Buffer Overflow Remote Code Execution Vulnerability. (bsc#1014437). This component is not built into our packages, so we are not affected.

Non security issues fixed:

• s3/client: obey 'disable netbios' smb.conf param, don't connect via NBT port; (bsc#1009085)

This update for samba fixes the following issues:

Security issues fixed:

• CVE-2016-2125: Don't send delegated credentials to all servers. (bsc#1014441).
• CVE-2016-2126: Denial of service due to a client triggered crash in the winbindd parent process. (bsc#1014442).
• CVE-2016-2123: Heap-based Buffer Overflow Remote Code Execution Vulnerability. (bsc#1014437). The component affected is not built in our packages.

Non security issues fixed:

• s3/client: obey 'disable netbios' smb.conf param, don't connect via NBT port; (bsc#1009085)
• Add doc changes for net ads --no-dns-updates switch; (bsc#991564)
• Include vfstest in samba-test; (bsc#1001203).
• s3/winbindd: using default domain with [email protected] format fails (bsc#997833).
• Fix illegal memory access after memory has been deleted (bsc#975299).
• Fix bug in tevent poll backend causing winbind to loop tightly (bsc#994500).
• Various fixes for spnego/ntlm (bsc#986675).

This update for samba fixes the following issues:

Security issues fixed:

• CVE-2016-2125: Don't send delegated credentials to all servers. (bsc#1014441).
• CVE-2016-2126: Denial of service due to a client triggered crash in the winbindd parent process. (bsc#1014442).
• CVE-2016-2123: Heap-based Buffer Overflow Remote Code Execution Vulnerability. (bsc#1014437). This issue does not affect our packages, as the component is not built.

Non security issues fixed:

• s3/client: obey 'disable netbios' smb.conf param, don't connect via NBT port (bsc#1009085)
• Add doc changes for net ads --no-dns-updates switch (bsc#991564)
• Include vfstest in samba-test (bsc#1001203).
• s3/winbindd: using default domain with [email protected] format fails (bsc#997833).
• Fix illegal memory access after memory has been deleted (bsc#975299).
• Fix bug in tevent poll backend causing winbind to loop tightly (bsc#994500).
• Various fixes for spnego/ntlm (bsc#986675).

Frederic Besler and others discovered that the ndr_pull_dnsp_nam function in Samba contained an integer overflow. An authenticated attacker could use this to gain administrative privileges. This issue only affected Ubuntu 14.04 LTS, Ubuntu 16.04 LTS, and Ubuntu 16.10. (CVE-2016-2123)

Simo Sorce discovered that that Samba clients always requested a forwardable ticket when using Kerberos authentication. An attacker could use this to impersonate an authenticated user or service. (CVE-2016-2125)

Volker Lendecke discovered that Kerberos PAC validation implementation in Samba contained multiple vulnerabilities. An authenticated attacker could use this to cause a denial of service or gain administrative privileges. This issue only affected Ubuntu 14.04 LTS, Ubuntu 16.04 LTS, and Ubuntu 16.10. (CVE-2016-2126)