libbpf, Buffer Overflow, CVE-2025-29481 (Critical)

How CVE-2025-29481 Works

The vulnerability in libbpf 1.5.0 arises due to improper bounds checking in the `bpf_object__init_prog` function. A local attacker can craft a malicious BPF object file that triggers a buffer overflow when processed by libbpf. By overflowing the buffer, the attacker can overwrite adjacent memory structures, leading to arbitrary code execution with the privileges of the process using libbpf. The flaw occurs when parsing specially designed program metadata, allowing an attacker to manipulate memory layouts and inject shellcode or redirect execution flow.

DailyCVE Form

Platform: Linux
Version: libbpf 1.5.0
Vulnerability: Buffer Overflow
Severity: Critical
Date: 04/15/2025

What Undercode Say:

Exploitation Analysis

1. Exploit Code (PoC Snippet):

include <bpf/libbpf.h>
int main() {
struct bpf_object obj = bpf_object__open("malicious_bpf.o");
bpf_object__load(obj); // Triggers overflow
return 0;
}

2. Crash Trigger Command:

gcc exploit.c -lbpf -o exploit && ./exploit

Protection & Mitigation

1. Patch: Upgrade to libbpf 1.5.1+.

2. Compiler Flags: Enable stack protection (`-fstack-protector-strong`).

3. System Hardening: Restrict BPF file permissions:

chmod 600 /usr/lib/libbpf.so.1.5.0

4. SELinux Policy: Enforce strict mode to limit BPF operations:

setenforce 1

Detection & Logging

1. Audit BPF Loads:

auditctl -w /usr/lib/libbpf.so.1.5.0 -p rwa -k libbpf_activity

2. GDB Debugging:

gdb -ex "run" --args ./target_program malicious_bpf.o

Forensics

1. Core Dump Analysis:

gdb ./exploit core -ex "bt full" -ex "quit"

2. Memory Inspection:

xxd /proc/$(pidof target_program)/maps | grep libbpf