CVE-2017-1000253

Think of the Linux kernel as the operating system’s “engine room.” This bug is about how the kernel places parts of a certain kind of program (PIE executables) into memory. If someone can run a local attack on an unpatched machine, they may be able to crash the system or—under the right conditions—cause it to run attacker-controlled code.

This matters to you if you run a Linux server and haven’t installed long-term kernel updates that include the 2015 fix for CVE-2017-1000253. It also specifically applies to systems using CentOS or Red Hat Enterprise Linux kernels that are still vulnerable.

It’s mainly a risk when a local attacker can run on the machine and your kernel matches the vulnerable version and settings (CONFIG_ARCH_BINFMT_ELF_RANDOMIZE_PIE enabled).

This is RED because CISA lists CVE-2017-1000253 in its KEV catalog and states it has been used in ransomware campaigns. That means attackers are not just theorizing about it—they’re using it in real attacks.

Act immediately to ensure the vulnerable kernel versions are patched or mitigated per your vendor instructions, with urgency matching the KEV remediation timeline.

1. Confirm exposure

   • Identify the running kernel version: check what your server reports as its kernel release/version.
   • Determine whether the kernel includes the fix commit a87938b2e246b81b4fb713edb371a9fa3c5c3c86 (or whether your distribution backported it into an updated long-term kernel build).
   • Confirm whether CONFIG_ARCH_BINFMT_ELF_RANDOMIZE_PIE is enabled in your running kernel configuration (your vendor documentation can help; some systems expose this via kernel config/feature reporting).

2. Compare to fixed versions

   • The known fixed baseline is: linux kernel fixed in 3.2.70.
   • For CentOS / Red Hat Enterprise Linux, install the vendor’s backported kernel update that corresponds to including the fix (your vendor’s advisory should state the patched kernel build).

3. Upgrade / patch plan

   • Schedule a kernel update window, reboot if required by your distribution, and then re-check the kernel version and configuration are as expected.
   • If multiple servers exist, prioritize those most exposed to untrusted local access (shared systems, systems with developer users, or systems where adversaries can get a foothold).

4. Temporary workaround if patching is delayed

   • Reduce the chance of a local attacker being present: tighten accounts and access controls, review user access, and limit who can log in or execute programs on the host.
   • Follow your distribution’s mitigation guidance from the vendor remediation references.

5. CISA KEV timeline

   • CISA remediation due date listed for this KEV item was 2024-09-30.
   • Treat this as overdue if any vulnerable kernel versions remain.

6. What to monitor after changes

   • After reboot, validate you are on the patched kernel baseline/backport.
   • Keep an eye on host logs for signs of compromise (especially indicators of ransomware activity), since the KEV listing ties this bug to real campaigns.

Severity is rated HIGH (CVSS 7.8). The mechanism relates to memory mapping overlap caused by improper consideration of address space needs when loading ELF PIE binaries.

Weakness type: CWE-119 (improper memory handling). Attack vector is local, with no user interaction required. Preconditions called out in findings: the system must run a vulnerable Linux kernel version not patched with commit a87938b2e246b81b4fb713edb371a9fa3c5c3c86, and CONFIG_ARCH_BINFMT_ELF_RANDOMIZE_PIE must be enabled. The problematic behavior involves load_elf_binary() mapping PIE segments in a way that can overlap regions intended to be “gaps” between the stack and binary mappings.

Exploitation status: confirmed real-world exploitation via CISA KEV listing (added 2024-09-09), with ransomware campaign usage and a remediation due date of 2024-09-30. No public exploit code is recorded in the findings. EPSS is provided as a prediction, but the KEV status is the dominant signal for urgency.