The branch, master has been updated via bfb8593 Samba 4.12.7, 4.11.13 and 4.10.18 Security Releases. via 7005929 NEWS[4.12.7]: Samba 4.12.7 Available for Download via b43f523 bla from bdd53f1 NEWS[4.13.0rc5]: Samba 4.13.0rc5 Available for Download
https://git.samba.org/?p=samba-web.git;a=shortlog;h=master - Log ----------------------------------------------------------------- commit bfb8593fd26fd5a611aeb5bcc9292f78190ecc37 Author: Karolin Seeger <ksee...@samba.org> Date: Fri Sep 18 14:05:18 2020 +0200 Samba 4.12.7, 4.11.13 and 4.10.18 Security Releases. Signed-off-by: Karolin Seeger <ksee...@samba.org> commit 700592980f58dc20461d4b5d7e2f743905861361 Author: Karolin Seeger <ksee...@samba.org> Date: Fri Sep 18 13:31:18 2020 +0200 NEWS[4.12.7]: Samba 4.12.7 Available for Download Signed-off-by: Karolin Seeger <ksee...@samba.org> commit b43f523e7bdb74f9f37172705c8ab17627e4aef3 Author: Karolin Seeger <ksee...@samba.org> Date: Fri Sep 18 13:54:00 2020 +0200 bla Signed-off-by: Karolin Seeger <ksee...@samba.org> ----------------------------------------------------------------------- Summary of changes: history/header_history.html | 3 + history/samba-4.12.7.html | 102 ++++++++++++ history/security.html | 19 +++ posted_news/20200918-115405.4.12.7.body.html | 36 ++++ posted_news/20200918-115405.4.12.7.headline.html | 4 + security/CVE-2020-1472.html | 200 +++++++++++++++++++++++ 6 files changed, 364 insertions(+) create mode 100644 history/samba-4.12.7.html create mode 100644 posted_news/20200918-115405.4.12.7.body.html create mode 100644 posted_news/20200918-115405.4.12.7.headline.html create mode 100644 security/CVE-2020-1472.html Changeset truncated at 500 lines: diff --git a/history/header_history.html b/history/header_history.html index 9aac8ce..ace0b76 100755 --- a/history/header_history.html +++ b/history/header_history.html @@ -9,6 +9,7 @@ <li><a href="/samba/history/">Release Notes</a> <li class="navSub"> <ul> + <li><a href="samba-4.12.7.html">samba-4.12.7</a></li> <li><a href="samba-4.12.6.html">samba-4.12.6</a></li> <li><a href="samba-4.12.5.html">samba-4.12.5</a></li> <li><a href="samba-4.12.4.html">samba-4.12.4</a></li> @@ -16,6 +17,7 @@ <li><a href="samba-4.12.2.html">samba-4.12.2</a></li> <li><a href="samba-4.12.1.html">samba-4.12.1</a></li> <li><a href="samba-4.12.0.html">samba-4.12.0</a></li> + <li><a href="samba-4.11.13.html">samba-4.11.13</a></li> <li><a href="samba-4.11.12.html">samba-4.11.12</a></li> <li><a href="samba-4.11.11.html">samba-4.11.11</a></li> <li><a href="samba-4.11.10.html">samba-4.11.10</a></li> @@ -29,6 +31,7 @@ <li><a href="samba-4.11.2.html">samba-4.11.2</a></li> <li><a href="samba-4.11.1.html">samba-4.11.1</a></li> <li><a href="samba-4.11.0.html">samba-4.11.0</a></li> + <li><a href="samba-4.10.18.html">samba-4.10.18</a></li> <li><a href="samba-4.10.17.html">samba-4.10.17</a></li> <li><a href="samba-4.10.16.html">samba-4.10.16</a></li> <li><a href="samba-4.10.15.html">samba-4.10.15</a></li> diff --git a/history/samba-4.12.7.html b/history/samba-4.12.7.html new file mode 100644 index 0000000..e9d7bd0 --- /dev/null +++ b/history/samba-4.12.7.html @@ -0,0 +1,102 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" + "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml"> +<head> +<title>Samba 4.12.7 - Release Notes</title> +</head> +<body> +<H2>Samba 4.12.7 Available for Download</H2> +<p> +<a href="https://download.samba.org/pub/samba/stable/samba-4.12.7.tar.gz">Samba 4.12.7 (gzipped)</a><br> +<a href="https://download.samba.org/pub/samba/stable/samba-4.12.7.tar.asc">Signature</a> +</p> +<p> +<a href="https://download.samba.org/pub/samba/patches/samba-4.12.6-4.12.7.diffs.gz">Patch (gzipped) against Samba 4.12.6</a><br> +<a href="https://download.samba.org/pub/samba/patches/samba-4.12.6-4.12.7.diffs.asc">Signature</a> +</p> +<p> +<pre> + ============================== + Release Notes for Samba 4.12.7 + September 18, 2020 + ============================== + + +This is a security release in order to address the following defect: + +o CVE-2020-1472: Unauthenticated domain takeover via netlogon ("ZeroLogon"). + +The following applies to Samba used as domain controller only (most +seriously the Active Directory DC, but also the classic/NT4-style DC). + +Installations running Samba as a file server only are not directly +affected by this flaw, though they may need configuration changes to +continue to talk to domain controllers (see "file servers and domain +members" below). + +The netlogon protocol contains a flaw that allows an authentication +bypass. This was reported and patched by Microsoft as CVE-2020-1472. +Since the bug is a protocol level flaw, and Samba implements the +protocol, Samba is also vulnerable. + +However, since version 4.8 (released in March 2018), the default +behaviour of Samba has been to insist on a secure netlogon channel, +which is a sufficient fix against the known exploits. This default is +equivalent to having 'server schannel = yes' in the smb.conf. + +Therefore versions 4.8 and above are not vulnerable unless they have +the smb.conf lines 'server schannel = no' or 'server schannel = auto'. + +Samba versions 4.7 and below are vulnerable unless they have 'server +schannel = yes' in the smb.conf. + +Note each domain controller needs the correct settings in its smb.conf. + +Vendors supporting Samba 4.7 and below are advised to patch their +installations and packages to add this line to the [global] section if +their smb.conf file. + +The 'server schannel = yes' smb.conf line is equivalent to Microsoft's +'FullSecureChannelProtection=1' registry key, the introduction of +which we understand forms the core of Microsoft's fix. + +Some domains employ third-party software that will not work with a +'server schannel = yes'. For these cases patches are available that +allow specific machines to use insecure netlogon. For example, the +following smb.conf: + + server schannel = yes + server require schannel:triceratops$ = no + server require schannel:greywacke$ = no + +will allow only "triceratops$" and "greywacke$" to avoid schannel. + +More details can be found here: +https://www.samba.org/samba/security/CVE-2020-1472.html + + +Changes since 4.12.6 +-------------------- + +o Jeremy Allison <j...@samba.org> + * BUG 14497: CVE-2020-1472(ZeroLogon): s3:rpc_server/netlogon: Protect + netr_ServerPasswordSet2 against unencrypted passwords. + +o Günther Deschner <g...@samba.org> + * BUG 14497: CVE-2020-1472(ZeroLogon): s3:rpc_server/netlogon: Support + "server require schannel:WORKSTATION$ = no" about unsecure configurations. + +o Gary Lockyer <g...@catalyst.net.nz> + * BUG 14497: CVE-2020-1472(ZeroLogon): s4 torture rpc: repeated bytes in + client challenge. + +o Stefan Metzmacher <me...@samba.org> + * BUG 14497: CVE-2020-1472(ZeroLogon): libcli/auth: Reject weak client + challenges in netlogon_creds_server_init() + "server require schannel:WORKSTATION$ = no". + + +</pre> +</p> +</body> +</html> diff --git a/history/security.html b/history/security.html index 3a1e672..92ac61e 100755 --- a/history/security.html +++ b/history/security.html @@ -26,6 +26,25 @@ link to full release notes for each release.</p> <td><em>Details</em></td> </tr> + <tr> + <td>18 Sep 2020</td> + <td><a href="/samba/ftp/patches/security/samba-4.12.6-security-2020-09-18.patch"> + patch for Samba 4.12.6</a><br /> + <a href="/samba/ftp/patches/security/samba-4.11.12-security-2020-09-18.patch"> + patch for Samba 4.11.12</a><br /> + <a href="/samba/ftp/patches/security/samba-4.10.17-security-2020-09-18.patch"> + patch for Samba 4.10.17</a><br /> + </td> + <td>CVE-2020-1472. + Please see announcements for details. + </td> + <td>Please refer to the advisory.</td> + <td><a href="https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-1472">CVE-2020-1472</a>. + </td> + <td><a href="/samba/security/CVE-2020-1472.html">Announcement</a>, + </td> + </tr> + <tr> <td>02 Jul 2020</td> <td><a href="/samba/ftp/patches/security/samba-4.12.3-security-2020-07-02.patch"> diff --git a/posted_news/20200918-115405.4.12.7.body.html b/posted_news/20200918-115405.4.12.7.body.html new file mode 100644 index 0000000..d5a58d0 --- /dev/null +++ b/posted_news/20200918-115405.4.12.7.body.html @@ -0,0 +1,36 @@ +<!-- BEGIN: posted_news/20200918-115405.4.12.7.body.html --> +<h5><a name="4.12.7">18 September 2020</a></h5> +<p class=headline>Samba 4.12.7, 4.11.13 and 4.10.18 Security Releases Available</p> +<p> +These are security releases in order to address +<a href="/samba/security/CVE-2020-1472.html">CVE-2020-1472</a> +(Unauthenticated domain takeover via netlogon ("ZeroLogon")). +</p> +<p> +The uncompressed tarballs have been signed using GnuPG (ID 6F33915B6568B7EA). +The source code can be <a +href="https://download.samba.org/pub/samba/stable/samba-4.12.7.tar.gz">downloaded +now</a>.</br> +A <a +href="https://download.samba.org/pub/samba/patches/samba-4.12.6-4.12.7.diffs.gz">patch +against Samba 4.12.6</a> is also available.</br> +See <a href="https://www.samba.org/samba/history/samba-4.12.7.html">the 4.12.7 +release notes </a> for more info.</br> +The source code can be <a +href="https://download.samba.org/pub/samba/stable/samba-4.11.13.tar.gz">downloaded +now</a>.</br> +A <a +href="https://download.samba.org/pub/samba/patches/samba-4.11.12-4.11.13.diffs.gz">patch +against Samba 4.11.13</a> is also available.</br> +See <a href="https://www.samba.org/samba/history/samba-4.11.13.html">the 4.11.13 +release notes</a> for more info.</br> +The source code can be <a +href="https://download.samba.org/pub/samba/stable/samba-4.10.18.tar.gz">downloaded +now</a>.</br> +A <a +href="https://download.samba.org/pub/samba/patches/samba-4.10.17-4.10.18.diffs.gz">patch +against Samba 4.10.17</a> is also available.</br> +See <a href="https://www.samba.org/samba/history/samba-4.10.18.html">the release +4.10.18 release notes</a> for more info.</br> +</p> +<!-- END: posted_news/20200918-115405.4.12.7.body.html --> diff --git a/posted_news/20200918-115405.4.12.7.headline.html b/posted_news/20200918-115405.4.12.7.headline.html new file mode 100644 index 0000000..0a3bef7 --- /dev/null +++ b/posted_news/20200918-115405.4.12.7.headline.html @@ -0,0 +1,4 @@ +<!-- BEGIN: posted_news/20200918-115405.4.12.7.headline.html --> +<li> 18 September 2020 <a href="#4.12.7">Samba 4.12.7, 4.11.13 and 4.10.18 +Security Releases Available</a></li> +<!-- END: posted_news/20200918-115405.4.12.7.headline.html --> diff --git a/security/CVE-2020-1472.html b/security/CVE-2020-1472.html new file mode 100644 index 0000000..bbe3ca4 --- /dev/null +++ b/security/CVE-2020-1472.html @@ -0,0 +1,200 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" + "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml"> + +<head> +<title>Samba - Security Announcement Archive</title> +</head> + +<body> + + <H2>CVE-2020-1472.html + +<p> +<pre> +=========================================================== +== Subject: Unauthenticated domain takeover via netlogon ("ZeroLogon") +== +== +== CVE ID#: CVE-2020-1472 +== +== Versions: Samba 4.0 and later +== +== Summary: An unauthenticated attacker on the network can gain +== administrator access by exploiting a netlogon +== protocol flaw. +=========================================================== + +=========== +Description +=========== + +The following applies to Samba used as domain controller only (most +seriously the Active Directory DC, but also the classic/NT4-style DC). + +Installations running Samba as a file server only are not directly +affected by this flaw, though they may need configuration changes to +continue to talk to domain controllers (see "file servers and domain +members" below). + +The netlogon protocol contains a flaw that allows an authentication +bypass. This was reported and patched by Microsoft as CVE-2020-1472. +Since the bug is a protocol level flaw, and Samba implements the +protocol, Samba is also vulnerable. + +However, since version 4.8 (released in March 2018), the default +behaviour of Samba has been to insist on a secure netlogon channel, +which is a sufficient fix against the known exploits. This default is +equivalent to having 'server schannel = yes' in the smb.conf. + +Therefore versions 4.8 and above are not vulnerable unless they have +the smb.conf lines 'server schannel = no' or 'server schannel = auto'. + +Samba versions 4.7 and below are vulnerable unless they have 'server +schannel = yes' in the smb.conf. + +Note each domain controller needs the correct settings in its smb.conf. + +Vendors supporting Samba 4.7 and below are advised to patch their +installations and packages to add this line to the [global] section if +their smb.conf file. + +The 'server schannel = yes' smb.conf line is equivalent to Microsoft's +'FullSecureChannelProtection=1' registry key, the introduction of +which we understand forms the core of Microsoft's fix. + +Consequences +============ + +The exploitation of this issue is by changing the a server password. +In an AD domain changing a DC password allows full password database +disclosure including the krbtgt password, unsalted MD4 password hash +(the 'NT Hash') for each user, and the LM password hash if stored. +(Via DRS replication). + +The krbtgt password allows the attacker to issue a 'golden ticket' to +themselves and return to take over the domain at any point in the +future. + +Other consequences includes disclosure of session keys, as well as +general denial of service to the trust account selected. + +Samba NT4-like / classic domains +================================ + +In NT4-like domains Samba does not provide a replication service (this +is done at lower layers, like OpenLDAP), but changing machine account +passwords can allow the attacker limited rights, similar to any other +member server or trusted domain. This includes disclosure of session +keys and inter-domain trust passwords (only), as well as general +denial of service to the domain member selected. + +Therefore while still real, the risk is lower in these domains than +for the AD DC. + +File servers and domain members +=============================== + +File servers and domain members do not run the NETLOGON service in +supported Samba versions and only need to ensure that they have not +set 'client schannel = no' for continued operation against secured DCs +such as Samba 4.8 and later and Windows DCs in 2021. Users running +Samba as a file server should still patch to ensure the server-side +mitigations (banning certain un-random values) do not very rarely +impact service. + +Allow listed exceptions +======================= + +Some domains employ third-party software that will not work with a +'server schannel = yes'. For these cases patches are available that +allow specific machines to use insecure netlogon. For example, the +following smb.conf: + + server schannel = yes + server require schannel:triceratops$ = no + server require schannel:greywacke$ = no + +will allow only "triceratops$" and "greywacke$" to avoid schannel. + +Exploitability of Samba despite 'server schannel = yes' +======================================================= + +The published proof of concept exploit for this issue only attempts to +authenticate to the NetLogon service but does not attempt a takeover of +the domain. + +On domains with 'server schannel = yes', these tests claim to show a +vulnerability against Samba despite being unable to access any +privileged functionality. + +This Samba release adds additional server checks for the protocol +attack in the client-specified challenge that provides some protection +when 'server schannel = no/auto' and avoids this false-positive +result. + +These server checks are identical to the server logic added by +Microsoft for their patch for the Windows server code for +CVE-2020-1472. The Samba Team would like to thank Microsoft for their +disclosure of the method used to prevent the proof of concept exploit +code from working against such a hardened server. + + +================== +Patch Availability +================== + +Patches addressing this defect are available at: + + https://www.samba.org/samba/security/ + +Additionally, Samba 4.10.18, 4.11.13, and 4.12.7 have been issued as +security releases to correct the defect. Samba administrators are +advised to upgrade to these releases or apply the patch as soon as +possible. + +================== +CVSSv3 calculation +================== + +CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H (9.8) + +========== +Workaround +========== + +Users of versions of Samba before 4.8 should set + + server schannel = yes + +in their smb.conf and restart Samba (on all domain controllers!) + +Users of versions 4.8 and above should ensure their smb.conf either +a) has the "server schannel = yes" line, or +b) has no "server schannel" line. + +If in doubt, add "server schannel = yes" to your smb.conf. + +======= +Credits +======= + +This problem was originally discovered by Tom Tervoort of Secura, +though it was not successfully reported to the Samba team before its +public disclosure. + +Stefan Metzmacher made the changes to Samba 4.8 that preemptively +dodge this bug in default installs. + +Andrew Bartlett, Gary Lockyer, Günther Deschner, Jeremy Allison, and +Stefan Metzmacher have triaged the bug and written patches and tests. + +This advisory written by Andrew Bartlett and Douglas Bagnall. + +========================================================== +== Our Code, Our Bugs, Our Responsibility. +== The Samba Team +========================================================== +</pre> +</body> +</html> -- Samba Website Repository