CVE-2024-6387
Published: July 2, 2024Last modified: July 8, 2024
Description
A signal handler race condition was found in OpenSSH's server (sshd), where a client does not authenticate within LoginGraceTime seconds (120 by default, 600 in old OpenSSH versions), then sshd's SIGALRM handler is called asynchronously. However, this signal handler calls various functions that are not async-signal-safe, for example, syslog().
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 8.1 |
| Attack Vector | NETWORK |
| Attack complexity | HIGH |
| Privileges required | NONE |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | HIGH |
| Integrity impact | HIGH |
| Availability impact | HIGH |
| Vector | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | openssh | Fixed (9.1_p1-r8) |
| Stream | openssh | Fixed (9.8_p1-r0) |
References
- http://seclists.org/fulldisclosure/2024/Jul/18
- http://seclists.org/fulldisclosure/2024/Jul/19
- http://seclists.org/fulldisclosure/2024/Jul/20
- http://www.openwall.com/lists/oss-security/2024/07/01/12
- http://www.openwall.com/lists/oss-security/2024/07/01/13
- http://www.openwall.com/lists/oss-security/2024/07/02/1
- http://www.openwall.com/lists/oss-security/2024/07/03/1
- http://www.openwall.com/lists/oss-security/2024/07/03/11
- http://www.openwall.com/lists/oss-security/2024/07/03/2
- http://www.openwall.com/lists/oss-security/2024/07/03/3
- http://www.openwall.com/lists/oss-security/2024/07/03/4
- http://www.openwall.com/lists/oss-security/2024/07/03/5
- http://www.openwall.com/lists/oss-security/2024/07/04/1
- http://www.openwall.com/lists/oss-security/2024/07/04/2
- http://www.openwall.com/lists/oss-security/2024/07/08/2
- http://www.openwall.com/lists/oss-security/2024/07/08/3
- http://www.openwall.com/lists/oss-security/2024/07/09/2
- http://www.openwall.com/lists/oss-security/2024/07/09/5
- http://www.openwall.com/lists/oss-security/2024/07/10/1
- http://www.openwall.com/lists/oss-security/2024/07/10/2
- http://www.openwall.com/lists/oss-security/2024/07/10/3
- http://www.openwall.com/lists/oss-security/2024/07/10/4
- http://www.openwall.com/lists/oss-security/2024/07/10/6
- http://www.openwall.com/lists/oss-security/2024/07/11/1
- http://www.openwall.com/lists/oss-security/2024/07/11/3
- http://www.openwall.com/lists/oss-security/2024/07/23/4
- http://www.openwall.com/lists/oss-security/2024/07/23/6
- http://www.openwall.com/lists/oss-security/2024/07/28/2
- http://www.openwall.com/lists/oss-security/2024/07/28/3
- https://access.redhat.com/errata/RHSA-2024:4312
- https://access.redhat.com/errata/RHSA-2024:4340
- https://access.redhat.com/errata/RHSA-2024:4389
- https://access.redhat.com/errata/RHSA-2024:4469
- https://access.redhat.com/errata/RHSA-2024:4474
- https://access.redhat.com/errata/RHSA-2024:4479
- https://access.redhat.com/errata/RHSA-2024:4484
- https://access.redhat.com/security/cve/CVE-2024-6387
- https://archlinux.org/news/the-sshd-service-needs-to-be-restarted-after-upgrading-to-openssh-98p1/
- https://arstechnica.com/security/2024/07/regresshion-vulnerability-in-openssh-gives-attackers-root-on-linux/
- https://blog.qualys.com/vulnerabilities-threat-research/2024/07/01/regresshion-remote-unauthenticated-code-execution-vulnerability-in-openssh-server
- https://bugzilla.redhat.com/show_bug.cgi?id=2294604
- https://explore.alas.aws.amazon.com/CVE-2024-6387.html
- https://forum.vmssoftware.com/viewtopic.php?f=8&t=9132
- https://ftp.netbsd.org/pub/NetBSD/security/advisories/NetBSD-SA2024-002.txt.asc
- https://github.com/AlmaLinux/updates/issues/629
- https://github.com/Azure/AKS/issues/4379
- https://github.com/PowerShell/Win32-OpenSSH/discussions/2248
- https://github.com/PowerShell/Win32-OpenSSH/issues/2249
- https://github.com/microsoft/azurelinux/issues/9555
- https://github.com/openela-main/openssh/commit/e1f438970e5a337a17070a637c1b9e19697cad09
- https://github.com/oracle/oracle-linux/issues/149
- https://github.com/rapier1/hpn-ssh/issues/87
- https://github.com/zgzhang/cve-2024-6387-poc
- https://lists.almalinux.org/archives/list/[email protected]/thread/23BF5BMGFVEVUI2WNVAGMLKT557EU7VY/
- https://lists.mindrot.org/pipermail/openssh-unix-announce/2024-July/000158.html
- https://lists.mindrot.org/pipermail/openssh-unix-dev/2024-July/041431.html
- https://news.ycombinator.com/item?id=40843778
- https://packetstorm.news/files/id/190587/
- https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2024-0010
- https://santandersecurityresearch.github.io/blog/sshing_the_masses.html
- https://security-tracker.debian.org/tracker/CVE-2024-6387
- https://security.netapp.com/advisory/ntap-20240701-0001/
- https://sig-security.rocky.page/issues/CVE-2024-6387/
- https://stackdiary.com/openssh-race-condition-in-sshd-allows-remote-code-execution/
- https://support.apple.com/kb/HT214118
- https://support.apple.com/kb/HT214119
- https://support.apple.com/kb/HT214120
- https://ubuntu.com/security/CVE-2024-6387
- https://ubuntu.com/security/notices/USN-6859-1
- https://www.akamai.com/blog/security-research/2024-openssh-vulnerability-regression-what-to-know-and-do
- https://www.arista.com/en/support/advisories-notices/security-advisory/19904-security-advisory-0100
- https://www.exploit-db.com/exploits/52269
- https://www.freebsd.org/security/advisories/FreeBSD-SA-24:04.openssh.asc
- https://www.openssh.com/txt/release-9.8
- https://www.qualys.com/2024/07/01/cve-2024-6387/regresshion.txt
- https://www.splunk.com/en_us/blog/security/cve-2024-6387-regresshion-vulnerability.html
- https://www.suse.com/security/cve/CVE-2024-6387.html
- https://www.theregister.com/2024/07/01/regresshion_openssh/
- https://www.vicarius.io/vsociety/posts/regresshion-an-openssh-regression-error-cve-2024-6387