From ddd08f913c80289e13e9c000e11c473a21ec23ca Mon Sep 17 00:00:00 2001 From: Ivan Nardi <12729895+IvanNardi@users.noreply.github.com> Date: Tue, 24 Sep 2024 14:20:31 +0200 Subject: Add some heuristics to detect encrypted/obfuscated/proxied TLS flows (#2553) Based on the paper: "Fingerprinting Obfuscated Proxy Traffic with Encapsulated TLS Handshakes". See: https://www.usenix.org/conference/usenixsecurity24/presentation/xue-fingerprinting Basic idea: * the packets/bytes distribution of a TLS handshake is quite unique * this fingerprint is still detectable if the handshake is encrypted/proxied/obfuscated All heuristics are disabled by default. --- fuzz/fuzz_config.cpp | 8 ++++++++ fuzz/fuzz_ndpi_reader.c | 2 ++ 2 files changed, 10 insertions(+) (limited to 'fuzz') diff --git a/fuzz/fuzz_config.cpp b/fuzz/fuzz_config.cpp index a23b74c30..0e8dda18d 100644 --- a/fuzz/fuzz_config.cpp +++ b/fuzz/fuzz_config.cpp @@ -129,6 +129,14 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) { ndpi_set_config(ndpi_info_mod, "tls", "application_blocks_tracking", cfg_value); ndpi_get_config(ndpi_info_mod, "tls", "application_blocks_tracking", cfg_value, sizeof(cfg_value)); } + if(fuzzed_data.ConsumeBool()) { + value = fuzzed_data.ConsumeIntegralInRange(0, 0x07 + 1); + snprintf(cfg_value, sizeof(cfg_value), "%d", value); + ndpi_set_config(ndpi_info_mod, "tls", "dpi.heuristics", cfg_value); + value = fuzzed_data.ConsumeIntegralInRange(0, 255 + 1); + snprintf(cfg_value, sizeof(cfg_value), "%d", value); + ndpi_set_config(ndpi_info_mod, "tls", "dpi.heuristics.max_packets_extra_dissection", cfg_value); + } if(fuzzed_data.ConsumeBool()) { value = fuzzed_data.ConsumeIntegralInRange(0, 1 + 1); snprintf(cfg_value, sizeof(cfg_value), "%d", value); diff --git a/fuzz/fuzz_ndpi_reader.c b/fuzz/fuzz_ndpi_reader.c index 2db6f696b..784e506d9 100644 --- a/fuzz/fuzz_ndpi_reader.c +++ b/fuzz/fuzz_ndpi_reader.c @@ -92,6 +92,8 @@ int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) { ndpi_set_config(workflow->ndpi_struct, "rtp", "search_for_stun", "1"); ndpi_set_config(workflow->ndpi_struct, "openvpn", "dpi.heuristics", "0x01"); ndpi_set_config(workflow->ndpi_struct, "openvpn", "dpi.heuristics.num_messages", "255"); + ndpi_set_config(workflow->ndpi_struct, "tls", "dpi.heuristics", "0x07"); + ndpi_set_config(workflow->ndpi_struct, "tls", "dpi.heuristics.max_packets_extra_dissection", "255"); ndpi_finalize_initialization(workflow->ndpi_struct); -- cgit v1.2.3