Red Hat Enterprise Linux 9: Concurrent Execution using Shared Resource with Improper Synchronization
CVE-2024-6387 is a high-severity concurrent execution using shared resource with improper synchronization vulnerability in Red Hat Enterprise Linux 9 from Red Hat, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 99.5% chance of exploitation within 30 days, which is in the top 0.06% of all scored CVEs.
Exploitation in the next 30 days is more likely than not, according to EPSS.
What to do
- Update SINAMICS IIoT module to V1.0 HF1 or a later version.
- Update SINEMA Remote Connect Server to V3.2 SP2 or a later version.
- Update SINUMERIK ONE to V6.24 or a later version.
- Read the advisory on ftp.netbsd.org for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
Version data comes from the organisation that assigned the CVE; 35 further products are omitted here. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.1 | High | CNA (redhat.com) |
| CVSS 3.1 | 8.1 | High | NVD |
Official description
A security regression (CVE-2006-5051) was discovered in OpenSSH's server (sshd). There is a race condition which can lead sshd to handle some signals in an unsafe manner. An unauthenticated, remote attacker may be able to trigger it by failing to authenticate within a set time period.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Concurrent Execution using Shared Resource with Improper Synchronization
The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.
How developers prevent this class of flaw
- In languages that support it, use synchronization primitives. Only wrap these around critical code to minimize the impact on performance.
- Use thread-safe capabilities such as the data access abstraction in Spring.
- Minimize the usage of shared resources in order to remove as much complexity as possible from the control flow and to reduce the likelihood of unexpected conditions occurring. Additionally, this will minimize the amount of synchronization necessary and may even help to reduce the likelihood of a denial of service where an attacker may be able to repeatedly trigger a critical section (CWE-400).
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Patches and release notes
- openssh.com/txt/release-9.8Release Notes, Third Party Advisory
- openwall.com/lists/oss-security/2024/07/03/3Mailing List
- github.com/openela-main/openssh/commit/e1f438970e5a337a17070a637c1b9e19697cad09
- lists.mindrot.org/pipermail/openssh-unix-announce/2024-July/000158.htmlMailing List, Release Notes
- lists.mindrot.org/pipermail/openssh-unix-dev/2024-July/041431.htmlMailing List
- news.ycombinator.com/item?id=40843778Issue Tracking
Third-party and government advisories
- access.redhat.com/errata/RHSA-2024:4312Third Party Advisory
- access.redhat.com/errata/RHSA-2024:4340Third Party Advisory
- access.redhat.com/errata/RHSA-2024:4389Third Party Advisory
- access.redhat.com/errata/RHSA-2024:4469Third Party Advisory
- access.redhat.com/errata/RHSA-2024:4474Third Party Advisory
- access.redhat.com/errata/RHSA-2024:4479Third Party Advisory
- access.redhat.com/errata/RHSA-2024:4484Third Party Advisory
- access.redhat.com/security/cve/CVE-2024-6387Third Party Advisory
- bugzilla.redhat.com/show_bug.cgi?id=2294604Third Party Advisory
- archlinux.org/news/the-sshd-service-needs-to-be-restarted-after-upgrading-to-openssh-98p1/Third Party Advisory
- arstechnica.com/security/2024/07/regresshion-vulnerability-in-openssh-gives-attackers-root-on-linux/Press/Media Coverage, Third Party Advisory
- blog.qualys.com/vulnerabilities-threat-research/2024/07/01/regresshion-remote-unauthenticated-code-execution-…Press/Media Coverage, Third Party Advisory
- explore.alas.aws.amazon.com/CVE-2024-6387.htmlThird Party Advisory
- github.com/zgzhang/cve-2024-6387-pocThird Party Advisory
- lists.almalinux.org/archives/list/[email protected]/thread/23BF5BMGFVEVUI2WNVAGMLKT557EU7VY/Third Party Advisory
Technical write-ups (may include proof of concept)
- santandersecurityresearch.github.io/blog/sshing_the_masses.htmlExploit, Third Party Advisory
- qualys.com/2024/07/01/cve-2024-6387/regresshion.txtExploit, Third Party Advisory
- openwall.com/lists/oss-security/2024/07/03/11Exploit, Mailing List
- openwall.com/lists/oss-security/2024/07/04/2Exploit, Mailing List
- openwall.com/lists/oss-security/2024/07/08/2Exploit, Mailing List
- openwall.com/lists/oss-security/2024/07/09/5Exploit, Mailing List
- openwall.com/lists/oss-security/2024/07/10/1Exploit, Mailing List
Other references
- seclists.org/fulldisclosure/2024/Jul/18Mailing List
- seclists.org/fulldisclosure/2024/Jul/19Mailing List
- seclists.org/fulldisclosure/2024/Jul/20Mailing List
- openwall.com/lists/oss-security/2024/07/01/12Mailing List
- openwall.com/lists/oss-security/2024/07/01/13Mailing List
- openwall.com/lists/oss-security/2024/07/02/1Mailing List
- openwall.com/lists/oss-security/2024/07/03/1Mailing List
- openwall.com/lists/oss-security/2024/07/03/2Mailing List
- openwall.com/lists/oss-security/2024/07/03/4Mailing List
- openwall.com/lists/oss-security/2024/07/03/5Mailing List
- openwall.com/lists/oss-security/2024/07/04/1Mailing List
- openwall.com/lists/oss-security/2024/07/08/3Mailing List
- openwall.com/lists/oss-security/2024/07/09/2Mailing List
- openwall.com/lists/oss-security/2024/07/10/2Mailing List
- openwall.com/lists/oss-security/2024/07/10/3Mailing List
Other vulnerabilities in Red Hat Enterprise Linux 9
- 7.5 High severity
- 7.5 High severity
- 7.9 High severity
- 7.3 High severity
- 7.5 High severity
- 7.8 High severity
Recent Concurrent Execution using Shared Resource with Improper Synchronization vulnerabilities
- 7.8 High severity
- 7.0 High severity
- 7.4 High severity
- 7.8 High severity
- 7.0 High severity
- 7.0 High severity
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