CVE-2023-4911

A buffer overflow was discovered in the GNU C Librarys 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.

Weakness

A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

Affected Software

Potential Mitigations

• 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 [REF-1334] discusses canary-based detection in detail.
• Run or compile the software using features or extensions that randomly arrange the positions of a program’s executable and libraries in memory. Because this makes the addresses unpredictable, it can prevent an attacker from reliably jumping to exploitable code.
• Examples include Address Space Layout Randomization (ASLR) [REF-58] [REF-60] and Position-Independent Executables (PIE) [REF-64]. Imported modules may be similarly realigned if their default memory addresses conflict with other modules, in a process known as “rebasing” (for Windows) and “prelinking” (for Linux) [REF-1332] using randomly generated addresses. ASLR for libraries cannot be used in conjunction with prelink since it would require relocating the libraries at run-time, defeating the whole purpose of prelinking.
• For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/92.html

References

• https://access.redhat.com/errata/RHSA-2023:5453
• https://access.redhat.com/errata/RHSA-2023:5454
• https://access.redhat.com/errata/RHSA-2023:5455
• https://access.redhat.com/errata/RHSA-2023:5476
• https://access.redhat.com/errata/RHSA-2024:0033
• https://access.redhat.com/security/cve/CVE-2023-4911
• https://bugzilla.redhat.com/show_bug.cgi?id=2238352
• https://www.qualys.com/2023/10/03/cve-2023-4911/looney-tunables-local-privilege-escalation-glibc-ld-so.txt
• https://www.qualys.com/cve-2023-4911/
• http://packetstormsecurity.com/files/174986/glibc-ld.so-Local-Privilege-Escalation.html
• http://packetstormsecurity.com/files/176288/Glibc-Tunables-Privilege-Escalation.html
• http://seclists.org/fulldisclosure/2023/Oct/11
• http://www.openwall.com/lists/oss-security/2023/10/03/2
• http://www.openwall.com/lists/oss-security/2023/10/03/3
• http://www.openwall.com/lists/oss-security/2023/10/05/1
• http://www.openwall.com/lists/oss-security/2023/10/13/11
• http://www.openwall.com/lists/oss-security/2023/10/14/3
• http://www.openwall.com/lists/oss-security/2023/10/14/5
• http://www.openwall.com/lists/oss-security/2023/10/14/6
• https://access.redhat.com/errata/RHSA-2023:5453
• https://access.redhat.com/errata/RHSA-2023:5454
• https://access.redhat.com/errata/RHSA-2023:5455
• https://access.redhat.com/errata/RHSA-2023:5476
• https://access.redhat.com/errata/RHSA-2024:0033
• https://access.redhat.com/security/cve/CVE-2023-4911
• https://bugzilla.redhat.com/show_bug.cgi?id=2238352
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4DBUQRRPB47TC3NJOUIBVWUGFHBJAFDL/
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/DFG4P76UHHZEWQ26FWBXG76N2QLKKPZA/
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NDAQWHTSVOCOZ5K6KPIWKRT3JX4RTZUR/
• https://security.gentoo.org/glsa/202310-03
• https://security.netapp.com/advisory/ntap-20231013-0006/
• https://www.debian.org/security/2023/dsa-5514
• https://www.qualys.com/2023/10/03/cve-2023-4911/looney-tunables-local-privilege-escalation-glibc-ld-so.txt
• https://www.qualys.com/cve-2023-4911/