CVE-2023-4911Exploited in the wildNVD status: Analyzed
GNU C Library Buffer Overflow
CVE-2023-4911 is a high-severity out-of-bounds write vulnerability in Red Hat Enterprise Linux 8 from Red Hat, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. CISA added it to the Known Exploited Vulnerabilities catalogue on November 21, 2023, which means attacks have been observed in the wild.
Patch now
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update SIMATIC S7-1500 TM MFP - GNU/Linux subsystem to V1.1 or a later version.
- Update Simatic S7-1500 Tm Mfp Firmware to 1.1 or a later version.
- Update Glibc to 2.39 or a later version.
- CISA's required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Affected products and versions
Version data comes from the organisation that assigned the CVE; 25 further products are omitted here. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- 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:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | CNA (redhat.com) |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
A buffer overflow was discovered in the GNU C Library's dynamic loader ld.so while processing the GLIBC_TUNABLES environment variable. This issue could allow a local attacker to use maliciously crafted GLIBC_TUNABLES environment variables when launching binaries with SUID permission to execute code with elevated privileges.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Out-of-bounds Write
The product writes data past the end, or before the beginning, of the intended buffer.
How developers prevent this class of flaw
- Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
- Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.
Timeline
- CVE record published.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- Deadline for US federal agencies to remediate, set by CISA.
- CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- bugzilla.redhat.com/show_bug.cgi?id=2238352Issue Tracking
Third-party and government advisories
- access.redhat.com/errata/RHSA-2023:5453Third Party Advisory
- access.redhat.com/errata/RHSA-2023:5454Third Party Advisory
- access.redhat.com/errata/RHSA-2023:5455Third Party Advisory
- access.redhat.com/errata/RHSA-2023:5476Third Party Advisory
- access.redhat.com/errata/RHSA-2024:0033Third Party Advisory
- access.redhat.com/security/cve/CVE-2023-4911Third Party Advisory
- qualys.com/cve-2023-4911/Third Party Advisory
- security.gentoo.org/glsa/202310-03Third Party Advisory
- security.netapp.com/advisory/ntap-20231013-0006/Third Party Advisory
- cert-portal.siemens.com/productcert/html/ssa-082556.htmlThird Party Advisory
- cert-portal.siemens.com/productcert/html/ssa-794697.htmlThird Party Advisory
- cert-portal.siemens.com/productcert/html/ssa-831302.htmlThird Party Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-4911US Government Resource
Technical write-ups (may include proof of concept)
- qualys.com/2023/10/03/cve-2023-4911/looney-tunables-local-privilege-escalation-glibc-ld-so.txtExploit, Third Party Advisory
- packetstormsecurity.com/files/174986/glibc-ld.so-Local-Privilege-Escalation.htmlExploit, Third Party Advisory, VDB Entry
- packetstormsecurity.com/files/176288/Glibc-Tunables-Privilege-Escalation.htmlExploit, Third Party Advisory, VDB Entry
- seclists.org/fulldisclosure/2023/Oct/11Exploit, Mailing List, Third Party Advisory
- openwall.com/lists/oss-security/2023/10/03/2Exploit, Mailing List
- exploit-db.com/exploits/52479Exploit, Third Party Advisory, VDB Entry
Other references
- openwall.com/lists/oss-security/2023/10/03/3Mailing List
- openwall.com/lists/oss-security/2023/10/05/1Mailing List
- openwall.com/lists/oss-security/2023/10/13/11Mailing List
- openwall.com/lists/oss-security/2023/10/14/3Mailing List
- openwall.com/lists/oss-security/2023/10/14/5Mailing List
- openwall.com/lists/oss-security/2023/10/14/6Mailing List
- lists.fedoraproject.org/archives/list/[email protected]/message/4DBUQRRPB47TC3NJOUIBVW…Mailing List
- lists.fedoraproject.org/archives/list/[email protected]/message/DFG4P76UHHZEWQ26FWBXG7…Mailing List
- lists.fedoraproject.org/archives/list/[email protected]/message/NDAQWHTSVOCOZ5K6KPIWKR…Mailing List
- debian.org/security/2023/dsa-5514Mailing List
Other vulnerabilities in Red Hat Enterprise Linux 8
- 7.8 High severity
- 7.5 High severity
- 7.5 High severity
- 7.9 High severity
- 7.3 High severity
- 7.5 High severity
Recent Out-of-bounds Write vulnerabilities
- 7.8 High severity
- 9.8 Critical severity
- 8.8 High severity
- 7.8 High severity
- 6.6 Medium severity
- 9.8 Critical severity
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