Bugzilla – Bug 936695
VUL-0: CVE-2015-5352: openssh: XSECURITY restrictions bypass
Last modified: 2019-03-15 19:42:12 UTC
http://www.openssh.com/txt/release-6.9 Security -------- * ssh(1): when forwarding X11 connections with ForwardX11Trusted=no, connections made after ForwardX11Timeout expired could be permitted and no longer subject to XSECURITY restrictions because of an ineffective timeout check in ssh(1) coupled with "fail open" behaviour in the X11 server when clients attempted connections with expired credentials. This problem was reported by Jann Horn. * ssh-agent(1): fix weakness of agent locking (ssh-add -x) to password guessing by implementing an increasing failure delay, storing a salted hash of the password rather than the password itself and using a timing-safe comparison function for verifying unlock attempts. This problem was reported by Ryan Castellucci. No CVEs assigned yet apparently.
(In reply to Marcus Meissner from comment #0) > * ssh(1): when forwarding X11 connections with ForwardX11Trusted=no, > connections made after ForwardX11Timeout expired could be permitted > and no longer subject to XSECURITY restrictions because of an > ineffective timeout check in ssh(1) coupled with "fail open" > behaviour in the X11 server when clients attempted connections with > expired credentials. This problem was reported by Jann Horn. https://anongit.mindrot.org/openssh.git/commit/?h=V_6_9&id=1bf477d3cdf1a864646d59820878783d42357a1d > * ssh-agent(1): fix weakness of agent locking (ssh-add -x) to > password guessing by implementing an increasing failure delay, > storing a salted hash of the password rather than the password > itself and using a timing-safe comparison function for verifying > unlock attempts. This problem was reported by Ryan Castellucci. https://anongit.mindrot.org/openssh.git/commit/?h=V_6_9&id=9173d0fbe44de7ebcad8a15618e13a8b8d78902e > No CVEs assigned yet apparently. Requesting.
CVE assigned for the first issue: http://seclists.org/oss-sec/2015/q3/9 > https://anongit.mindrot.org/openssh.git/commit/?h=V_6_9& > id=1bf477d3cdf1a864646d59820878783d42357a1d > > > Use CVE-2015-5352 for the issue in which the refusal deadline was not > checked within the x11_open_helper function. There is some concern about additional changes: > (There's extra code to > make the x11_refuse_time value usable within two source-code files, > but adding that code doesn't seem to be related to any independent > problem.) Also for moving code: > We didn't completely understand the rationale for moving "system(cmd)" > after the x11_refuse_time assignment, or whether this is addressing an > independent problem.[...] Asked upstream for comment on this: > The scope of CVE-2015-5352 does not include any fail-open > characteristics of an X server. There could possibly be a separate CVE > ID if there is an error that needs to be fixed in the X codebase. On the other issue: > * ssh-agent(1): fix weakness of agent locking (ssh-add -x) to > password guessing by implementing an increasing failure delay, > storing a salted hash of the password rather than the password > itself and using a timing-safe comparison function for verifying > unlock attempts. > > > Our current thought is that a CVE ID may not be needed because attacks > against ssh-agent locking don't cross a privilege boundary. In other > words, the changelog entry could be interpreted to mean addition of a > new security feature related to a threat model that wasn't in the > previous design goals (e.g., password guessing by malware running > under the same account). I have asked upstream for comment.
A write up for CVE-2015-5352: https://thejh.net/written-stuff/openssh-6.8-xsecurity
(In reply to Marcus Meissner from comment #5) > A write up for CVE-2015-5352: > https://thejh.net/written-stuff/openssh-6.8-xsecurity do skes11sp3 &sles11sp1 & sles10sp4 affected by this cve.
(In reply to Jason Dian from comment #6) > (In reply to Marcus Meissner from comment #5) > > A write up for CVE-2015-5352: > > https://thejh.net/written-stuff/openssh-6.8-xsecurity > do skes11sp3 &sles11sp1 & sles10sp4 affected by this cve. (In reply to Marcus Meissner from comment #5) > A write up for CVE-2015-5352: > https://thejh.net/written-stuff/openssh-6.8-xsecurity when will the patch be released ?
Digest of impact: A malicious SSH server could gain compromising access to the X session of a client connecting with ssh -X Adjusting severity.
An update workflow for this issue was started. This issue was rated as moderate. Please submit fixed packages until 2015-07-29. When done, reassign the bug to security-team@suse.de. https://swamp.suse.de/webswamp/wf/62212
For the X11 timeouting mechanism: If certain versions dont support that feature/protection, we dont need to port that feature just to fix it. If there is no such option, we dont need to fix that. For the agent-locking: The salting/hashing patch sounds like very intrusive with the risk of breaking other things. IMHO it would be sufficient to just use the increased-delay and time-constant-compare part of the patchset to fix openssh versions that dont have blowfish and bcrypt-pbkdf available. For all other distros which have the feaures and building blocks available, they should get the "full" patch.
Hm, timingsafe_bcmp arrived at about the same time blowfish and bcrypt-pbkdf did. Still it's rather straightforward.
the patchs have been in QA for long time. customer want to know when they will be released ?
QA: no reproducer available at this time.
SUSE-SU-2015:1544-1: An update that solves 5 vulnerabilities and has one errata is now available. Category: security (moderate) Bug References: 903649,932483,936695,938746,943006,943010 CVE References: CVE-2015-4000,CVE-2015-5352,CVE-2015-5600,CVE-2015-6563,CVE-2015-6564 Sources used: SUSE Linux Enterprise Server 12 (src): openssh-6.6p1-29.1, openssh-askpass-gnome-6.6p1-29.1 SUSE Linux Enterprise Desktop 12 (src): openssh-6.6p1-29.1, openssh-askpass-gnome-6.6p1-29.1
SUSE-SU-2015:1547-1: An update that solves 5 vulnerabilities and has 5 fixes is now available. Category: security (moderate) Bug References: 673532,903649,905118,914309,916549,932483,936695,938746,943006,943010 CVE References: CVE-2015-4000,CVE-2015-5352,CVE-2015-5600,CVE-2015-6563,CVE-2015-6564 Sources used: SUSE Linux Enterprise Server for VMWare 11-SP3 (src): openssh-6.2p2-0.17.1, openssh-askpass-gnome-6.2p2-0.17.3 SUSE Linux Enterprise Server 11-SP3 (src): openssh-6.2p2-0.17.1, openssh-askpass-gnome-6.2p2-0.17.3
SUSE-SU-2015:1547-2: An update that solves 5 vulnerabilities and has 5 fixes is now available. Category: security (moderate) Bug References: 673532,903649,905118,914309,916549,932483,936695,938746,943006,943010 CVE References: CVE-2015-4000,CVE-2015-5352,CVE-2015-5600,CVE-2015-6563,CVE-2015-6564 Sources used: SUSE Linux Enterprise Desktop 11-SP3 (src): openssh-6.2p2-0.17.1, openssh-askpass-gnome-6.2p2-0.17.3 SUSE Linux Enterprise Debuginfo 11-SP3 (src): openssh-6.2p2-0.17.1, openssh-askpass-gnome-6.2p2-0.17.3
SUSE-SU-2015:1581-1: An update that solves 5 vulnerabilities and has 6 fixes is now available. Category: security (important) Bug References: 673532,903649,905118,914309,916549,932483,936695,938746,943006,943010,945493 CVE References: CVE-2015-4000,CVE-2015-5352,CVE-2015-5600,CVE-2015-6563,CVE-2015-6564 Sources used: SUSE Linux Enterprise Server for VMWare 11-SP3 (src): openssh-6.2p2-0.21.1, openssh-askpass-gnome-6.2p2-0.21.3 SUSE Linux Enterprise Server 11-SP3 (src): openssh-6.2p2-0.21.1, openssh-askpass-gnome-6.2p2-0.21.3 SUSE Linux Enterprise Desktop 11-SP3 (src): openssh-6.2p2-0.21.1, openssh-askpass-gnome-6.2p2-0.21.3 SUSE Linux Enterprise Debuginfo 11-SP3 (src): openssh-6.2p2-0.21.1, openssh-askpass-gnome-6.2p2-0.21.3
An update workflow for this issue was started. This issue was rated as moderate. Please submit fixed packages until 2015-10-21. When done, reassign the bug to security-team@suse.de. https://swamp.suse.de/webswamp/wf/62308
SUSE-SU-2015:1695-1: An update that solves 5 vulnerabilities and has 5 fixes is now available. Category: security (moderate) Bug References: 903649,932483,936695,938746,939932,943006,943010,945484,945493,947458 CVE References: CVE-2015-4000,CVE-2015-5352,CVE-2015-5600,CVE-2015-6563,CVE-2015-6564 Sources used: SUSE Linux Enterprise Server 11-SP4 (src): openssh-6.6p1-13.1, openssh-askpass-gnome-6.6p1-13.3 SUSE Linux Enterprise Desktop 11-SP4 (src): openssh-6.6p1-13.1, openssh-askpass-gnome-6.6p1-13.3 SUSE Linux Enterprise Debuginfo 11-SP4 (src): openssh-6.6p1-13.1, openssh-askpass-gnome-6.6p1-13.3
SUSE-SU-2015:1840-1: An update that solves three vulnerabilities and has four fixes is now available. Category: security (moderate) Bug References: 673532,903649,905118,914309,932483,936695,938746 CVE References: CVE-2015-4000,CVE-2015-5352,CVE-2015-5600 Sources used: SUSE Linux Enterprise Server 11-SP2-LTSS (src): openssh-5.1p1-41.69.1, openssh-askpass-gnome-5.1p1-41.69.4
Guys, does this issue get fixed in SLES 11SP1?
the issue affects sles 11 sp1, but no, sles 11 sp1 is out of support and did not get fixed.
(In reply to Marcus Meissner from comment #31) > the issue affects sles 11 sp1, but no, sles 11 sp1 is out of support and did > not get fixed. Hi Marcus, According to the comment#9 of bug#938277, CVE-2015-5352 is no affect. Could you check again and give me a confirm? Thanks, Xuanke Han
This is an autogenerated message for OBS integration: This bug (936695) was mentioned in https://build.opensuse.org/request/show/398334 13.2 / openssh
Dear Petr,Does this PTF complete to test? My customers test this PTF and face the issue at ssh client connection as below: OMM1:~/CVE-2015-5352 # ls openssh-5.1p1-41.55.1.9388.0.PTF.948086.x86_64.rpm openssh-askpass-5.1p1-41.55.1.9388.0.PTF.948086.x86_64.rpm OMM1:~/CVE-2015-5352 # rpm -qa |grep openssh openssh-askpass-5.1p1-41.31.36 openssh-5.1p1-41.31.36 OMM1:~/CVE-2015-5352 # rpm -Uvh openssh-5.1p1-41.55.1.9388.0.PTF.948086.x86_64.rpm openssh-askpass-5.1p1-41.55.1.9388.0.PTF.948086.x86_64.rpm Preparing... ########################################### [100%] 1:openssh ########################################### [ 50%] Updating etc/sysconfig/ssh... Starting SuSEconfig, the SuSE Configuration Tool... Running module permissions only Reading /etc/sysconfig and updating the system... Executing /sbin/conf.d/SuSEconfig.permissions... Finished. 2:openssh-askpass ########################################### [100%] OMM1:~/CVE-2015-5352 # rcsshd restart Shutting down SSH daemon done Starting SSH daemon done OMM1:~/CVE-2015-5352 # rcsshd restart Shutting down SSH daemon done Starting SSH daemon done OMM1:~/CVE-2015-5352 # /bin/netstat -nlp | grep sshd tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 3873/sshd OMM1:~/CVE-2015-5352 # ssh 127.0.0.1 The authenticity of host '127.0.0.1 (127.0.0.1)' can't be established. RSA key fingerprint is af:94:2c:27:94:dc:bc:2c:f8:38:5e:66:37:bd:bd:53. Are you sure you want to continue connecting (yes/no)? yes Warning: Permanently added '127.0.0.1' (RSA) to the list of known hosts. Last login: Fri Jul 15 08:49:52 2016 from 192.168.10.9 OMM1:~/CVE-2015-5352 # ssh 192.168.10.110 The authenticity of host '192.168.10.110 (192.168.10.110)' can't be established. RSA key fingerprint is af:94:2c:27:94:dc:bc:2c:f8:38:5e:66:37:bd:bd:53. Are you sure you want to continue connecting (yes/no)? yes Warning: Permanently added '192.168.10.110' (RSA) to the list of known hosts. Last login: Fri Jul 15 09:01:22 2016 from localhost OMM1:~ # OMM1:~ # root@hatest02 ~]# ssh root@192.168.10.110 Connection closed by 192.168.10.110 [root@hatest02 ~]# ssh -vv root@192.168.10.110 OpenSSH_5.3p1, OpenSSL 1.0.0-fips 29 Mar 2010 debug1: Reading configuration data /root/.ssh/config debug1: Reading configuration data /etc/ssh/ssh_config debug1: Applying options for * debug2: ssh_connect: needpriv 0 debug1: Connecting to 192.168.10.110 [192.168.10.110] port 22. debug1: Connection established. debug1: permanently_set_uid: 0/0 debug1: identity file /root/.ssh/identity type -1 debug2: key_type_from_name: unknown key type '-----BEGIN' debug2: key_type_from_name: unknown key type '-----END' debug1: identity file /root/.ssh/id_rsa type 1 debug1: identity file /root/.ssh/id_dsa type -1 debug1: Remote protocol version 2.0, remote software version OpenSSH_5.1 debug1: match: OpenSSH_5.1 pat OpenSSH* debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-OpenSSH_5.3 debug2: fd 3 setting O_NONBLOCK debug1: SSH2_MSG_KEXINIT sent debug1: SSH2_MSG_KEXINIT received debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1 debug2: kex_parse_kexinit: ssh-rsa,ssh-dss debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: none,zlib@openssh.com,zlib debug2: kex_parse_kexinit: none,zlib@openssh.com,zlib debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: first_kex_follows 0 debug2: kex_parse_kexinit: reserved 0 debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1 debug2: kex_parse_kexinit: ssh-rsa,ssh-dss debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour128,arcfour256,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour128,arcfour256,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: none,zlib@openssh.com debug2: kex_parse_kexinit: none,zlib@openssh.com debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: first_kex_follows 0 debug2: kex_parse_kexinit: reserved 0 debug2: mac_setup: found hmac-md5 debug1: kex: server->client aes128-ctr hmac-md5 none debug2: mac_setup: found hmac-md5 debug1: kex: client->server aes128-ctr hmac-md5 none debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP Connection closed by 192.168.10.110 [root@hatest02 ~]# OMM1:~ # tailf /var/log/messages Jul 15 08:49:52 OMM1 sshd[3716]: Accepted publickey for root from 192.168.10.9 port 59326 ssh2 Jul 15 08:50:17 OMM1 shadow[3767]: group already exists - group=sshd, by=0 Jul 15 08:50:17 OMM1 useradd[3768]: account already exists - account=sshd, by=0 Jul 15 08:50:18 OMM1 sshd[3678]: Received signal 15; terminating. Jul 15 08:50:18 OMM1 sshd[3813]: Server listening on 0.0.0.0 port 22. Jul 15 08:50:28 OMM1 sshd[3813]: Received signal 15; terminating. Jul 15 08:50:28 OMM1 sshd[3843]: Server listening on 0.0.0.0 port 22. Jul 15 08:50:32 OMM1 sshd[3843]: Received signal 15; terminating. Jul 15 08:50:32 OMM1 sshd[3873]: Server listening on 0.0.0.0 port 22. Jul 15 08:51:14 OMM1 sshd[3879]: Accepted publickey for root from 127.0.0.1 port 11688 ssh2 ^C OMM1:~ # /bin/netstat -nlp | grep sshd tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 3873/sshd OMM1:~ # lsof -i :22 COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME ^C OMM1:~ # lsof -n -i :22 COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME sshd 3716 root 3r IPv4 9506 0t0 TCP 192.168.10.110:ssh->192.168.10.9:59326 (ESTABLISHED) sshd 3873 root 3u IPv4 9902 0t0 TCP *:ssh (LISTEN) ssh 3878 root 3u IPv4 9990 0t0 TCP 127.0.0.1:11688->127.0.0.1:ssh (ESTABLISHED) sshd 3879 root 3r IPv4 9991 0t0 TCP 127.0.0.1:ssh->127.0.0.1:11688 (ESTABLISHED) OMM1:~ # and exit it cost long time. OMM1:~ # exit logout Connection to 127.0.0.1 closed. OMM1:~/CVE-2015-5352 # ssh 127.0.0.1 Last login: Fri Jul 15 08:51:14 2016 from localhost OMM1:~ # exit
An update workflow for this issue was started. This issue was rated as important. Please submit fixed packages until 2017-01-18. When done, reassign the bug to security-team@suse.de. https://swamp.suse.de/webswamp/wf/63340
posted note: "The ForwardX11Timeout feature was added in openssh 5.6p1, so older versions are not affected by this security issue."