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How the CVE Works
CVE-2025-30356 is a critical heap buffer overflow vulnerability in CryptoLib versions 1.3.3 and earlier, used in the CCSDS Space Data Link Security Protocol (SDLS-EP). The flaw exists in the `Crypto_TC_ApplySecurity` function due to insufficient validation of the `fl` (frame length) field. While CVE-2025-29912 patched an underflow issue, the fix did not fully prevent unsafe calculations. An attacker can craft malicious frames with manipulated `fl` values, causing `tf_payload_len` to become negative. When interpreted as an unsigned integer, this triggers an oversized memory copy (memcpy), leading to heap corruption, potential remote code execution, or system crashes.
DailyCVE Form
Platform: CryptoLib
Version: ≤1.3.3
Vulnerability: Heap Buffer Overflow
Severity: Critical
Date: 04/29/2025
What Undercode Say:
Exploitation:
- Craft a malicious SDLS-EP frame with a manipulated `fl` field.
- Force `tf_payload_len` to a negative value, which becomes a large unsigned value.
- Trigger heap overflow via
memcpy, corrupting adjacent memory.
Detection & Exploit Code:
// Proof-of-Concept (PoC) Snippet
void exploit_sdls_ep() {
uint8_t malicious_frame[bash];
memset(malicious_frame, 0x41, sizeof(malicious_frame));
// Set invalid fl to trigger underflow
malicious_frame[bash] = 0xFF;
send_to_target(malicious_frame);
}
Mitigation:
1. Patch: Upgrade to CryptoLib >1.3.3.
2. Input Validation: Sanitize `fl` field before processing.
- Bounds Checking: Ensure `tf_payload_len` is non-negative before
memcpy.
Analytics:
- Attack Vector: Remote (network-exploitable).
- Impact: RCE, DoS, or data leakage.
- CVSS 4.0: 9.3 (AV:N/AC:L/PR:N/UI:N/VC:H/VI:H/VA:H).
Protection Commands:
Check CryptoLib version $ crypto_lib --version Apply workaround (if patch unavailable) $ firewall --block-port SDLS_EP_PORT
Debugging:
(gdb) break Crypto_TC_ApplySecurity (gdb) watch (int)tf_payload_len
References:
(End of report, no additional commentary.)
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
