ID

VAR-201901-1500

CVE

CVE-2018-20685

TITLE

OpenSSH Access control vulnerability

DESCRIPTION

In OpenSSH 7.9, scp.c in the scp client allows remote SSH servers to bypass intended access restrictions via the filename of . or an empty filename. The impact is modifying the permissions of the target directory on the client side. OpenSSH Contains an access control vulnerability.Information may be tampered with. OpenSSH is prone to an access-bypass vulnerability. An attacker can exploit this issue to bypass certain security restrictions and perform unauthorized actions; this may aid in launching further attacks. OpenSSH version 7.9 is vulnerable. ========================================================================== Ubuntu Security Notice USN-3885-1 February 07, 2019 openssh vulnerabilities ========================================================================== A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 18.10 - Ubuntu 18.04 LTS - Ubuntu 16.04 LTS - Ubuntu 14.04 LTS Summary: Several security issues were fixed in OpenSSH. Update instructions: The problem can be corrected by updating your system to the following package versions: Ubuntu 18.10: openssh-client 1:7.7p1-4ubuntu0.2 Ubuntu 18.04 LTS: openssh-client 1:7.6p1-4ubuntu0.2 Ubuntu 16.04 LTS: openssh-client 1:7.2p2-4ubuntu2.7 Ubuntu 14.04 LTS: openssh-client 1:6.6p1-2ubuntu2.12 In general, a standard system update will make all the necessary changes. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Gentoo Linux Security Advisory GLSA 201903-16 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - https://security.gentoo.org/ - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Severity: Normal Title: OpenSSH: Multiple vulnerabilities Date: March 20, 2019 Bugs: #675520, #675522 ID: 201903-16 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Synopsis ======== Multiple vulnerabilities have been found in OpenSSH, the worst of which could allow a remote attacker to gain unauthorized access. Affected packages ================= ------------------------------------------------------------------- Package / Vulnerable / Unaffected ------------------------------------------------------------------- 1 net-misc/openssh < 7.9_p1-r4 >= 7.9_p1-r4 Description =========== Multiple vulnerabilities have been discovered in OpenSSH. Please review the CVE identifiers referenced below for details. Workaround ========== There is no known workaround at this time. Resolution ========== All OpenSSH users should upgrade to the latest version: # emerge --sync # emerge --ask --oneshot --verbose ">=net-misc/openssh-7.9_p1-r4" References ========== [ 1 ] CVE-2018-20685 https://nvd.nist.gov/vuln/detail/CVE-2018-20685 [ 2 ] CVE-2019-6109 https://nvd.nist.gov/vuln/detail/CVE-2019-6109 [ 3 ] CVE-2019-6110 https://nvd.nist.gov/vuln/detail/CVE-2019-6110 [ 4 ] CVE-2019-6111 https://nvd.nist.gov/vuln/detail/CVE-2019-6111 Availability ============ This GLSA and any updates to it are available for viewing at the Gentoo Security Website: https://security.gentoo.org/glsa/201903-16 Concerns? ========= Security is a primary focus of Gentoo Linux and ensuring the confidentiality and security of our users' machines is of utmost importance to us. Any security concerns should be addressed to security@gentoo.org or alternatively, you may file a bug at https://bugs.gentoo.org. License ======= Copyright 2019 Gentoo Foundation, Inc; referenced text belongs to its owner(s). The contents of this document are licensed under the Creative Commons - Attribution / Share Alike license. https://creativecommons.org/licenses/by-sa/2.5 . -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 ===================================================================== Red Hat Security Advisory Synopsis: Moderate: openssh security, bug fix, and enhancement update Advisory ID: RHSA-2019:3702-01 Product: Red Hat Enterprise Linux Advisory URL: https://access.redhat.com/errata/RHSA-2019:3702 Issue date: 2019-11-05 CVE Names: CVE-2018-20685 CVE-2019-6109 CVE-2019-6111 ===================================================================== 1. Summary: An update for openssh is now available for Red Hat Enterprise Linux 8. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section. Relevant releases/architectures: Red Hat Enterprise Linux AppStream (v. 8) - aarch64, ppc64le, s390x, x86_64 Red Hat Enterprise Linux BaseOS (v. 8) - aarch64, ppc64le, s390x, x86_64 3. Description: OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server. The following packages have been upgraded to a later upstream version: openssh (8.0p1). Additional Changes: For detailed information on changes in this release, see the Red Hat Enterprise Linux 8.1 Release Notes linked from the References section. Solution: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 After installing this update, the OpenSSH server daemon (sshd) will be restarted automatically. 1686065 - SSH connections get closed when time-based rekeyring is used and ClientAliveMaxCount=0 1691045 - Rebase OpenSSH to latest release (8.0p1?) 1707485 - Use high-level API to do signatures 1712436 - MD5 is used when writing password protected PEM 1732424 - ssh-keygen -A fails in FIPS mode because of DSA key 1732449 - rsa-sha2-*-cert-v01@openssh.com host key types are ignored in FIPS despite being in the policy 6. Package List: Red Hat Enterprise Linux AppStream (v. 8): aarch64: openssh-askpass-8.0p1-3.el8.aarch64.rpm openssh-askpass-debuginfo-8.0p1-3.el8.aarch64.rpm openssh-cavs-debuginfo-8.0p1-3.el8.aarch64.rpm openssh-clients-debuginfo-8.0p1-3.el8.aarch64.rpm openssh-debuginfo-8.0p1-3.el8.aarch64.rpm openssh-debugsource-8.0p1-3.el8.aarch64.rpm openssh-keycat-debuginfo-8.0p1-3.el8.aarch64.rpm openssh-ldap-debuginfo-8.0p1-3.el8.aarch64.rpm openssh-server-debuginfo-8.0p1-3.el8.aarch64.rpm pam_ssh_agent_auth-debuginfo-0.10.3-7.3.el8.aarch64.rpm ppc64le: openssh-askpass-8.0p1-3.el8.ppc64le.rpm openssh-askpass-debuginfo-8.0p1-3.el8.ppc64le.rpm openssh-cavs-debuginfo-8.0p1-3.el8.ppc64le.rpm openssh-clients-debuginfo-8.0p1-3.el8.ppc64le.rpm openssh-debuginfo-8.0p1-3.el8.ppc64le.rpm openssh-debugsource-8.0p1-3.el8.ppc64le.rpm openssh-keycat-debuginfo-8.0p1-3.el8.ppc64le.rpm openssh-ldap-debuginfo-8.0p1-3.el8.ppc64le.rpm openssh-server-debuginfo-8.0p1-3.el8.ppc64le.rpm pam_ssh_agent_auth-debuginfo-0.10.3-7.3.el8.ppc64le.rpm s390x: openssh-askpass-8.0p1-3.el8.s390x.rpm openssh-askpass-debuginfo-8.0p1-3.el8.s390x.rpm openssh-cavs-debuginfo-8.0p1-3.el8.s390x.rpm openssh-clients-debuginfo-8.0p1-3.el8.s390x.rpm openssh-debuginfo-8.0p1-3.el8.s390x.rpm openssh-debugsource-8.0p1-3.el8.s390x.rpm openssh-keycat-debuginfo-8.0p1-3.el8.s390x.rpm openssh-ldap-debuginfo-8.0p1-3.el8.s390x.rpm openssh-server-debuginfo-8.0p1-3.el8.s390x.rpm pam_ssh_agent_auth-debuginfo-0.10.3-7.3.el8.s390x.rpm x86_64: openssh-askpass-8.0p1-3.el8.x86_64.rpm openssh-askpass-debuginfo-8.0p1-3.el8.x86_64.rpm openssh-cavs-debuginfo-8.0p1-3.el8.x86_64.rpm openssh-clients-debuginfo-8.0p1-3.el8.x86_64.rpm openssh-debuginfo-8.0p1-3.el8.x86_64.rpm openssh-debugsource-8.0p1-3.el8.x86_64.rpm openssh-keycat-debuginfo-8.0p1-3.el8.x86_64.rpm openssh-ldap-debuginfo-8.0p1-3.el8.x86_64.rpm openssh-server-debuginfo-8.0p1-3.el8.x86_64.rpm pam_ssh_agent_auth-debuginfo-0.10.3-7.3.el8.x86_64.rpm Red Hat Enterprise Linux BaseOS (v. 8): Source: openssh-8.0p1-3.el8.src.rpm aarch64: openssh-8.0p1-3.el8.aarch64.rpm openssh-askpass-debuginfo-8.0p1-3.el8.aarch64.rpm openssh-cavs-8.0p1-3.el8.aarch64.rpm openssh-cavs-debuginfo-8.0p1-3.el8.aarch64.rpm openssh-clients-8.0p1-3.el8.aarch64.rpm openssh-clients-debuginfo-8.0p1-3.el8.aarch64.rpm openssh-debuginfo-8.0p1-3.el8.aarch64.rpm openssh-debugsource-8.0p1-3.el8.aarch64.rpm openssh-keycat-8.0p1-3.el8.aarch64.rpm openssh-keycat-debuginfo-8.0p1-3.el8.aarch64.rpm openssh-ldap-8.0p1-3.el8.aarch64.rpm openssh-ldap-debuginfo-8.0p1-3.el8.aarch64.rpm openssh-server-8.0p1-3.el8.aarch64.rpm openssh-server-debuginfo-8.0p1-3.el8.aarch64.rpm pam_ssh_agent_auth-0.10.3-7.3.el8.aarch64.rpm pam_ssh_agent_auth-debuginfo-0.10.3-7.3.el8.aarch64.rpm ppc64le: openssh-8.0p1-3.el8.ppc64le.rpm openssh-askpass-debuginfo-8.0p1-3.el8.ppc64le.rpm openssh-cavs-8.0p1-3.el8.ppc64le.rpm openssh-cavs-debuginfo-8.0p1-3.el8.ppc64le.rpm openssh-clients-8.0p1-3.el8.ppc64le.rpm openssh-clients-debuginfo-8.0p1-3.el8.ppc64le.rpm openssh-debuginfo-8.0p1-3.el8.ppc64le.rpm openssh-debugsource-8.0p1-3.el8.ppc64le.rpm openssh-keycat-8.0p1-3.el8.ppc64le.rpm openssh-keycat-debuginfo-8.0p1-3.el8.ppc64le.rpm openssh-ldap-8.0p1-3.el8.ppc64le.rpm openssh-ldap-debuginfo-8.0p1-3.el8.ppc64le.rpm openssh-server-8.0p1-3.el8.ppc64le.rpm openssh-server-debuginfo-8.0p1-3.el8.ppc64le.rpm pam_ssh_agent_auth-0.10.3-7.3.el8.ppc64le.rpm pam_ssh_agent_auth-debuginfo-0.10.3-7.3.el8.ppc64le.rpm s390x: openssh-8.0p1-3.el8.s390x.rpm openssh-askpass-debuginfo-8.0p1-3.el8.s390x.rpm openssh-cavs-8.0p1-3.el8.s390x.rpm openssh-cavs-debuginfo-8.0p1-3.el8.s390x.rpm openssh-clients-8.0p1-3.el8.s390x.rpm openssh-clients-debuginfo-8.0p1-3.el8.s390x.rpm openssh-debuginfo-8.0p1-3.el8.s390x.rpm openssh-debugsource-8.0p1-3.el8.s390x.rpm openssh-keycat-8.0p1-3.el8.s390x.rpm openssh-keycat-debuginfo-8.0p1-3.el8.s390x.rpm openssh-ldap-8.0p1-3.el8.s390x.rpm openssh-ldap-debuginfo-8.0p1-3.el8.s390x.rpm openssh-server-8.0p1-3.el8.s390x.rpm openssh-server-debuginfo-8.0p1-3.el8.s390x.rpm pam_ssh_agent_auth-0.10.3-7.3.el8.s390x.rpm pam_ssh_agent_auth-debuginfo-0.10.3-7.3.el8.s390x.rpm x86_64: openssh-8.0p1-3.el8.x86_64.rpm openssh-askpass-debuginfo-8.0p1-3.el8.x86_64.rpm openssh-cavs-8.0p1-3.el8.x86_64.rpm openssh-cavs-debuginfo-8.0p1-3.el8.x86_64.rpm openssh-clients-8.0p1-3.el8.x86_64.rpm openssh-clients-debuginfo-8.0p1-3.el8.x86_64.rpm openssh-debuginfo-8.0p1-3.el8.x86_64.rpm openssh-debugsource-8.0p1-3.el8.x86_64.rpm openssh-keycat-8.0p1-3.el8.x86_64.rpm openssh-keycat-debuginfo-8.0p1-3.el8.x86_64.rpm openssh-ldap-8.0p1-3.el8.x86_64.rpm openssh-ldap-debuginfo-8.0p1-3.el8.x86_64.rpm openssh-server-8.0p1-3.el8.x86_64.rpm openssh-server-debuginfo-8.0p1-3.el8.x86_64.rpm pam_ssh_agent_auth-0.10.3-7.3.el8.x86_64.rpm pam_ssh_agent_auth-debuginfo-0.10.3-7.3.el8.x86_64.rpm These packages are GPG signed by Red Hat for security. Our key and details on how to verify the signature are available from https://access.redhat.com/security/team/key/ 7. References: https://access.redhat.com/security/cve/CVE-2018-20685 https://access.redhat.com/security/cve/CVE-2019-6109 https://access.redhat.com/security/cve/CVE-2019-6111 https://access.redhat.com/security/updates/classification/#moderate https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/8.1_release_notes/ 8. Contact: The Red Hat security contact is <secalert@redhat.com>. More contact details at https://access.redhat.com/security/team/contact/ Copyright 2019 Red Hat, Inc. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIVAwUBXcHzKNzjgjWX9erEAQiytQ/6Apphov2V0QmnXA+KO3ZZKBPXtgKv8Sv1 dPtXhTC+Keq4yX9/bXlIuyk6BUsMeaiIMlL5bSSKtq2I7rVxwubTcPX4rD+pQvx8 ArNJgn7U2/3xqwc0R8dNXx6o8vB1M6jXDtu8fKJOxW48evDJf6gE4gX2KUM9yxR2 MhCoHVkLp9a5f0T11yFPI11H0P8gXXQgboAkdt82Ui35T4tD8RndVyPCsllN2c/X QCCbvZ9e8OLJJoxsOryLcw8tpQHXK2AJMXWv0Us99kQtbaBULWWahhrg/tftLxtT pILFBaB/RsmGg1O6OkxJ2CuKl6ATC2Wlj/Z7uYPrS7MQDn+fXkH2gfcjb4Z4rqIL IyKbUpsyFEAaV5rJUeRaS7dGfuQldQbS96P8lUpCcOXPbYD8FgTrW2q3NjOKgYMU +gh2xPwmlRm+iYfmedPoR2+bTWNYv8JS+Cp/fZF4IFx2EJPQcxKLYshNKgcfkNkR rIZ4brUI79p84H01TcTh4mFAbR63Y+c36UAI3/fM/W/RkZn/PdoJtpfwg/tjOYZH rt9kL7SfAEhjHNtBuJGNol6e124srS6300hnfFovAr6llDOcYlrh3ZgVZjVrn6E8 TZhyZ84TGMOqykfH7B9XkJH82X+x3rd2m0ovCPq+Ly62BasdXVd0C2snzbx8OAM8 I+am8dhVlyM= =iPw4 -----END PGP SIGNATURE----- -- RHSA-announce mailing list RHSA-announce@redhat.com https://www.redhat.com/mailman/listinfo/rhsa-announce . scp client multiple vulnerabilities =================================== The latest version of this advisory is available at: https://sintonen.fi/advisories/scp-client-multiple-vulnerabilities.txt Overview -------- SCP clients from multiple vendors are susceptible to a malicious scp server performing unauthorized changes to target directory and/or client output manipulation. Description ----------- Many scp clients fail to verify if the objects returned by the scp server match those it asked for. This issue dates back to 1983 and rcp, on which scp is based. Finally, two vulnerabilities in clients may allow server to spoof the client output. Details ------- The discovered vulnerabilities, described in more detail below, enables the attack described here in brief. 1. The attacker controlled server or Man-in-the-Middle(*) attack drops .bash_aliases file to victim's home directory when the victim performs scp operation from the server. The transfer of extra files is hidden by sending ANSI control sequences via stderr. For example: user@local:~$ scp user@remote:readme.txt . readme.txt 100% 494 1.6KB/s 00:00 user@local:~$ 2. Once the victim launches a new shell, the malicious commands in .bash_aliases get executed. *) Man-in-the-Middle attack does require the victim to accept the wrong host fingerprint. Vulnerabilities --------------- 1. 2. CWE-20: scp client missing received object name validation [CVE-2019-6111] Due to the scp implementation being derived from 1983 rcp [1], the server chooses which files/directories are sent to the client. However, scp client only perform cursory validation of the object name returned (only directory traversal attacks are prevented). A malicious scp server can overwrite arbitrary files in the scp client target directory. If recursive operation (-r) is performed, the server can manipulate subdirectories as well (for example overwrite .ssh/authorized_keys). The same vulnerability in WinSCP is known as CVE-2018-20684. 3. CWE-451: scp client spoofing via object name [CVE-2019-6109] Due to missing character encoding in the progress display, the object name can be used to manipulate the client output, for example to employ ANSI codes to hide additional files being transferred. 4. CWE-451: scp client spoofing via stderr [CVE-2019-6110] Due to accepting and displaying arbitrary stderr output from the scp server, a malicious server can manipulate the client output, for example to employ ANSI codes to hide additional files being transferred. Proof-of-Concept ---------------- Proof of concept malicious scp server will be released at a later date. Vulnerable versions ------------------- The following software packages have some or all vulnerabilities: ver #1 #2 #3 #4 OpenSSH scp <=7.9 x x x x PuTTY PSCP ? - - x x WinSCP scp mode <=5.13 - x - - Tectia SSH scpg3 is not affected since it exclusively uses sftp protocol. Mitigation ---------- 1. OpenSSH 1.1 Switch to sftp if possible 1.2 Alternatively apply the following patch to harden scp against most server-side manipulation attempts: https://sintonen.fi/advisories/scp-name-validator.patch NOTE: This patch may cause problems if the the remote and local shells don't agree on the way glob() pattern matching works. YMMV. 2. PuTTY 2.1 No fix is available yet 3. WinSCP 3.1. Upgrade to WinSCP 5.14 or later Similar or prior work --------------------- 1. CVE-2000-0992 - scp overwrites arbitrary files References ---------- 1. https://www.jeffgeerling.com/blog/brief-history-ssh-and-remote-access Credits ------- The vulnerability was discovered by Harry Sintonen / F-Secure Corporation. Timeline -------- 2018.08.08 initial discovery of vulnerabilities #1 and #2 2018.08.09 reported vulnerabilities #1 and #2 to OpenSSH 2018.08.10 OpenSSH acknowledged the vulnerabilities 2018.08.14 discovered & reported vulnerability #3 to OpenSSH 2018.08.15 discovered & reported vulnerability #4 to OpenSSH 2018.08.30 reported PSCP vulnerabilities (#3 and #4) to PuTTY developers 2018.08.31 reported WinSCP vulnerability (#2) to WinSCP developers 2018.09.04 WinSCP developers reported the vulnerability #2 fixed 2018.11.12 requested a status update from OpenSSH 2018.11.16 OpenSSH fixed vulnerability #1 2019.01.07 requested a status update from OpenSSH 2019.01.08 requested CVE assignments from MITRE 2019.01.10 received CVE assignments from MITRE 2019.01.11 public disclosure of the advisory 2019.01.14 added a warning about the potential issues caused by the patch . All the vulnerabilities are in found in the scp client implementing the SCP protocol. The check added in this version can lead to regression if the client and the server have differences in wildcard expansion rules. If the server is trusted for that purpose, the check can be disabled with a new -T option to the scp client. For the stable distribution (stretch), these problems have been fixed in version 1:7.4p1-10+deb9u5. For the detailed security status of openssh please refer to its security tracker page at: https://security-tracker.debian.org/tracker/openssh Further information about Debian Security Advisories, how to apply these updates to your system and frequently asked questions can be found at: https://www.debian.org/security/ Mailing list: debian-security-announce@lists.debian.org -----BEGIN PGP SIGNATURE----- iQEzBAEBCgAdFiEE8vi34Qgfo83x35gF3rYcyPpXRFsFAlxe0w0ACgkQ3rYcyPpX RFs85AgA0GrSHO4Qf5FVsE3oXa+nMkZ4U6pbOA9dHotX54DEyNuIJrOsOv01cFxQ t2Z6uDkZptmHZT4uSWg2xIgMvpkGo9906ziZfHc0LTuHl8j++7cCDIDGZBm/iZaX ueQfl85gHDpte41JvUtpSBAwk1Bic7ltLUPDIGEiq6nQboxHIzsU7ULVb1l0wNxF sEFDPWGBS01HTa+QWgQaG/wbEhMRDcVz1Ck7dqpT2soQRohDWxU01j14q1EKe9O9 GHiWECvFSHBkkI/v8lNfSWnOWYa/+Aknri0CpjPc/bqh2Yx9rgp/Q5+FJ/FxJjmC bHFd+tbxB1LxEO96zKguYpPIzw7Kcw== =5Fd8 -----END PGP SIGNATURE-----

AFFECTED PRODUCTS

CVSS

PROBLEMTYPE DATA

THREAT TYPE

remote

TYPE

access control error

CONFIGURATIONS

PATCH

EXTERNAL IDS

REFERENCES

CREDITS

Red Hat,Harry Sintonen,Gentoo

SOURCES

LAST UPDATE DATE

2024-11-23T19:42:50.345000+00:00

SOURCES UPDATE DATE

SOURCES RELEASE DATE