CVE-2025-0007

Executive Summary

CVE-2025-0007 is a local privilege escalation vulnerability in the Xilinx Run Time (XRT) framework. The flaw stems from insufficient input validation, allowing a local attacker with user-level access to escalate privileges to kernel space. This can lead to full compromise of confidentiality, integrity, and availability of the affected system. The vulnerability has a CVSS score of 5.7 (Medium), but the potential impact is high due to the kernel-level access. No public proof-of-concept or patch details are currently available.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It affects the Xilinx Run Time framework, which is a proprietary component of Xilinx FPGA development tools.

CVSS Breakdown & Threat Level

• CVSS Score: 5.7 (Medium)
• Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
• Attack Vector: Local (AV:L)
• Attack Complexity: Low (AC:L)
• Privileges Required: Low (PR:L)
• User Interaction: None (UI:N)
• Scope: Unchanged (S:U)
• Confidentiality Impact: High (C:H)
• Integrity Impact: High (I:H)
• Availability Impact: High (A:H)

Threat Level: Medium. While the CVSS score is medium, the impact is high due to kernel-level access. The low attack complexity and low privileges required make it a significant threat for local attackers.

Deep Dive & Mechanics

The vulnerability exists in the Xilinx Run Time (XRT) framework, which provides user-space libraries and kernel drivers for managing Xilinx FPGA devices. The insufficient validation occurs when user-space applications interact with the kernel driver via ioctl calls or other system calls. Specifically, the driver does not properly validate input parameters, such as buffer sizes, offsets, or pointers, before using them in kernel operations.

This lack of validation can be exploited by a local attacker to:

1. Trigger a buffer overflow: By providing oversized or malformed input, the attacker can overwrite kernel memory.
2. Achieve arbitrary kernel write: By manipulating pointers or offsets, the attacker can write controlled data to arbitrary kernel addresses.
3. Escalate privileges: By overwriting kernel structures (e.g., process credentials), the attacker can gain root privileges.

The vulnerability is likely in the XRT kernel module (e.g., xocl.ko or xclmgmt.ko), which handles communication between user-space and the FPGA hardware.

Vulnerable vs. Patched Code

Since no patch details are available, a hypothetical vulnerable code snippet and its patched version are provided.

Vulnerable Code (C - Kernel Module):

static long xrt_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) {
    struct xrt_ioctl_args args;
    if (copy_from_user(&args, (void __user *)arg, sizeof(args))) {
        return -EFAULT;
    }
    // No validation of args.size or args.offset
    void *kernel_buf = kmalloc(args.size, GFP_KERNEL);
    if (copy_from_user(kernel_buf, args.user_ptr, args.size)) {
        kfree(kernel_buf);
        return -EFAULT;
    }
    // Use kernel_buf without bounds checking
    process_data(kernel_buf, args.size);
    kfree(kernel_buf);
    return 0;
}

Patched Code (C - Kernel Module):

static long xrt_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) {
    struct xrt_ioctl_args args;
    if (copy_from_user(&args, (void __user *)arg, sizeof(args))) {
        return -EFAULT;
    }
    // Validate args.size
    if (args.size > MAX_BUF_SIZE || args.size == 0) {
        return -EINVAL;
    }
    // Validate user_ptr
    if (!access_ok(args.user_ptr, args.size)) {
        return -EFAULT;
    }
    void *kernel_buf = kmalloc(args.size, GFP_KERNEL);
    if (!kernel_buf) {
        return -ENOMEM;
    }
    if (copy_from_user(kernel_buf, args.user_ptr, args.size)) {
        kfree(kernel_buf);
        return -EFAULT;
    }
    // Use kernel_buf with validated size
    process_data(kernel_buf, args.size);
    kfree(kernel_buf);
    return 0;
}

Exploitation & Lab Setup

Red Team

Prerequisites:

• Local user access on a system with Xilinx XRT installed.
• Knowledge of the vulnerable ioctl command number.

Exploitation Steps:

1. Identify the vulnerable device: Enumerate /dev/xclmgmt* or /dev/dri/renderD* devices.
2. Craft a malicious payload: Create a user-space program that sends a crafted ioctl call with oversized or malformed data.
3. Trigger the vulnerability: Execute the program to trigger the buffer overflow or arbitrary write.
4. Escalate privileges: Use the kernel write to overwrite the current process's credentials (e.g., modify cred struct) to gain root.

Example Exploit Code (C - User Space):

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <string.h>
#include <unistd.h>

#define XRT_IOCTL_CMD 0x1234
#define PAYLOAD_SIZE 0x1000

struct xrt_ioctl_args {
    void *user_ptr;
    size_t size;
};

int main() {
    int fd = open("/dev/xclmgmt0", O_RDWR);
    if (fd < 0) {
        perror("open");
        return 1;
    }

    // Craft payload to overwrite kernel memory
    char *payload = malloc(PAYLOAD_SIZE);
    memset(payload, 'A', PAYLOAD_SIZE);
    // Place shellcode or credential overwrite at specific offset
    // ...

    struct xrt_ioctl_args args;
    args.user_ptr = payload;
    args.size = PAYLOAD_SIZE; // Oversized to trigger overflow

    if (ioctl(fd, XRT_IOCTL_CMD, &args) < 0) {
        perror("ioctl");
        return 1;
    }

    printf("Exploit triggered. Check for root shell.\n");
    close(fd);
    return 0;
}

Blue Team

Detection Steps:

1. Monitor ioctl calls: Use auditd to log all ioctl calls to XRT devices.
2. Check for unusual kernel module activity: Monitor dmesg for kernel oops or crashes.
3. Analyze process behavior: Look for processes with low privileges attempting to interact with /dev/xclmgmt* devices.
4. Review system logs: Check /var/log/syslog or /var/log/messages for XRT-related errors.

Hunting Queries:

• Sysmon (Windows): Not applicable (Linux vulnerability).
• Auditd Rule:

  -w /dev/xclmgmt* -p rwxa -k xrt_ioctl
  

Indicators of Compromise (IOCs)

• File Hashes: Unknown (no known malware).
• Network Indicators: None (local vulnerability).
• Process Names: exploit (or custom binary name).
• Kernel Module: xocl.ko, xclmgmt.ko (loaded).
• System Calls: Abnormal ioctl calls to XRT devices.
• Log Entries: Kernel oops messages in dmesg related to XRT.

Detection Engineering

YARA Rule

rule CVE_2025_0007_XRT_Exploit {
    meta:
        description = "Detects potential exploit binaries for CVE-2025-0007 targeting Xilinx XRT"
        author = "Valters IT"
        date = "2025-01-01"
        reference = "CVE-2025-0007"
    strings:
        $ioctl_cmd = { 34 12 00 00 } // XRT_IOCTL_CMD in little endian
        $xrt_device = "/dev/xclmgmt" ascii
        $payload_size = { 00 10 00 00 } // PAYLOAD_SIZE 0x1000
    condition:
        all of them
}

Sigma Rule

title: CVE-2025-0007 XRT Privilege Escalation Attempt
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects attempts to exploit CVE-2025-0007 via ioctl calls to XRT devices
author: Valters IT
date: 2025-01-01
logsource:
    product: linux
    service: auditd
detection:
    selection:
        type: SYSCALL
        syscall: ioctl
        path: /dev/xclmgmt*
    condition: selection
falsepositives:
    - Legitimate XRT usage by authorized users
level: high

Suricata Rule

alert ip any any -> any any (msg:"CVE-2025-0007 XRT Privilege Escalation Attempt"; content:"/dev/xclmgmt"; nocase; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Restrict access to XRT devices: Use chmod or udev rules to limit access to trusted users only.
2. Monitor for exploitation: Implement the detection rules above.
3. Apply vendor patch: Once available, update XRT to the patched version.

Long-term Mitigation:

• Principle of Least Privilege: Ensure users have minimal necessary permissions.
• Kernel Hardening: Enable SELinux or AppArmor to restrict kernel module interactions.
• Regular Updates: Keep XRT and all system software up to date.

Workaround:

• Unload the XRT kernel module when not in use:

  sudo rmmod xocl
  sudo rmmod xclmgmt
  

Valters IT
Securing Digital Frontiers