Junglewise Threat Intelligence

CVE-2024-33601: GNU glibc denial of service in nscd netgroup cache

CVE-2024-33601 · Severity: high · CVSS 7.3 · Published 2024-05-06

Executive brief

The GNU C Library (glibc) contains a flaw in its Name Service Cache Daemon (nscd), a service used to speed up lookups for network resources and user groups. An attacker can trigger a memory allocation failure that causes the daemon to crash and stop responding. This results in a denial of service, potentially preventing users and applications from accessing network resources or logging into the system.

Technical details

The Name Service Cache Daemon (nscd) in glibc uses xmalloc or xrealloc within its netgroup cache implementation. These functions are designed to terminate the process if a memory allocation failure occurs. An attacker can exploit this by sending specific requests that trigger an out-of-memory (OOM) condition in the netgroup cache, leading to a daemon crash (Denial of Service). While xmalloc is used in other parts of nscd, those instances typically occur during startup; the netgroup cache usage is vulnerable because it can be triggered by client requests during runtime. The vulnerability was introduced in glibc 2.15 and is fixed in version 2.40 and various backported stable releases.

Affected products

  • GNU glibc 2.15 to 2.39
  • Debian Debian Linux 10.0
  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP >= V3.1.5

Timeline

  • 2024-04-24: disclosed: Public date for GLIBC-SA-2024-0007
  • 2024-05-06: advisory: NVD published date
  • 2024-06-30: patched: Debian LTS update released
  • 2024-07-22: patched: glibc 2.40 released with fix

References

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