cbcvebase.
CVE-2023-4911
published 2023-10-03

CVE-2023-4911: 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…

PriorityP192high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
KEVITWEXPLOITRansomware
CISA Known Exploited Vulnerabilitydue 2023-12-12
Exploited in the wild
EPSS
81.42%
99.6th percentile
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.

Affected

79 ranges· showing 25
VendorProductVersion rangeFixed in
canonicalubuntu_linux
canonicalubuntu_linux
debiandebian_linux
debiandebian_linux
debianglibc< glibc 2.36-9+deb12u3 (bookworm)glibc 2.36-9+deb12u3 (bookworm)
fedoraprojectfedora
fedoraprojectfedora
fedoraprojectfedora
gnuglibc>= 0 < 2.31-13+deb11u72.31-13+deb11u7
gnuglibc>= 0 < 2.36-9+deb12u32.36-9+deb12u3
gnuglibc>= 0 < 2.37-122.37-12
gnuglibc>= 0 < 2.37-122.37-12
gnuglibc>= 0 < 2.35-0ubuntu3.42.35-0ubuntu3.4
gnuglibc>= 2.34 < 2.392.39
msrcazl3_glibc_2.38-10_on_azure_linux_3.0
msrcazl3_glibc_2.38-6_on_azure_linux_3.0
msrcazure_linux_3.0_arm
msrcazure_linux_3.0_x64
msrccbl2_glibc_2.35-5_on_cbl_mariner_2.0
msrccbl_mariner_2.0_arm
msrccbl_mariner_2.0_x64
redhatcodeready_linux_builder
redhatcodeready_linux_builder_eus
redhatcodeready_linux_builder_eus
redhatcodeready_linux_builder_eus

Detection & IOCsextracted from sources · hover to see the quote

path/etc/ld.so.preload
otherGLIBC_TUNABLES (maliciously crafted environment variable)
  • Monitor for manipulation of the GLIBC_TUNABLES environment variable when SUID binaries are launched, as this is the direct exploitation vector for CVE-2023-4911.
  • Alert on writes to /etc/ld.so.preload, which is used by Kinsing to load its rootkit for persistence after exploiting CVE-2023-4911.
  • Monitor crontab modifications for entries that download and execute scripts every minute, a persistence mechanism used by Kinsing post-exploitation.
  • CVE-2023-4911 affects default installations of Debian 12/13, Ubuntu 22.04/23.04, and Fedora 37/38; prioritize detection and patching on these platforms.
  • Alpine Linux (musl libc) is NOT affected by CVE-2023-4911; focus detection efforts on glibc-based distributions only.
  • Kinsing exploits CVE-2023-4911 to steal cloud service provider (CSP) credentials; monitor for credential access activity on cloud-hosted Linux systems.
  • ·The vulnerability was introduced in glibc in April 2021; systems running glibc versions predating this are not affected.
  • ·Exploitation requires local access and the ability to set environment variables for SUID binaries; remote exploitation is not directly possible without a prior foothold.

CVSS provenance

nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
osv7.8HIGH
vulncheck7.8HIGH
cisa7.8HIGH
vendor_debian7.8HIGH
vendor_msrc7.8HIGH
vendor_oracle7.8HIGH
vendor_redhat7.8HIGH
vendor_ubuntu6.5MEDIUM
CVEs like this are exactly what “Exploited This Week” covers.

Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.