diff --git a/doc/userguide/rules/dhcp-keywords.rst b/doc/userguide/rules/dhcp-keywords.rst new file mode 100644 index 0000000000..adac122b29 --- /dev/null +++ b/doc/userguide/rules/dhcp-keywords.rst @@ -0,0 +1,21 @@ +DHCP keywords +============= + +dhcp.leasetime +-------------- + +DHCP lease time (integer). + +Syntax:: + + dhcp.leasetime:[op] + +The version can be matched exactly, or compared using the _op_ setting:: + + dhcp.leasetime:3 # exactly 3 + dhcp.leasetime:<3 # smaller than 3 + dhcp.leasetime:>=2 # greater or equal than 2 + +Signature example:: + + alert dhcp any any -> any any (msg:"small DHCP lease time (<3)"; dhcp.leasetime:<3; sid:1; rev:1;) diff --git a/doc/userguide/rules/index.rst b/doc/userguide/rules/index.rst index 4ef87bdeb8..5c0db48ced 100644 --- a/doc/userguide/rules/index.rst +++ b/doc/userguide/rules/index.rst @@ -19,6 +19,7 @@ Suricata Rules ja3-keywords modbus-keyword dcerpc-keywords + dhcp-keywords dnp3-keywords enip-keyword ftp-keywords diff --git a/doc/userguide/rules/intro.rst b/doc/userguide/rules/intro.rst index e5b92b5449..d3e3321b54 100644 --- a/doc/userguide/rules/intro.rst +++ b/doc/userguide/rules/intro.rst @@ -88,6 +88,7 @@ you can pick from. These are: * smb * dns * dcerpc +* dhcp * ssh * smtp * imap diff --git a/rust/src/dhcp/detect.rs b/rust/src/dhcp/detect.rs new file mode 100644 index 0000000000..c257f94c2c --- /dev/null +++ b/rust/src/dhcp/detect.rs @@ -0,0 +1,34 @@ +/* Copyright (C) 2022 Open Information Security Foundation + * + * You can copy, redistribute or modify this Program under the terms of + * the GNU General Public License version 2 as published by the Free + * Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * version 2 along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ + +use super::dhcp::{DHCPTransaction, DHCP_OPT_ADDRESS_TIME}; +use super::parser::DHCPOptionWrapper; + +#[no_mangle] +pub unsafe extern "C" fn rs_dhcp_tx_get_leasetime( + tx: &mut DHCPTransaction, leasetime: *mut u64, +) -> u8 { + for option in &tx.message.options { + if option.code == DHCP_OPT_ADDRESS_TIME { + if let DHCPOptionWrapper::TimeValue(ref time_value) = option.option { + *leasetime = time_value.seconds as u64; + return 1; + } + } + } + return 0; +} diff --git a/rust/src/dhcp/mod.rs b/rust/src/dhcp/mod.rs index b34dd9859c..bc859d7b54 100644 --- a/rust/src/dhcp/mod.rs +++ b/rust/src/dhcp/mod.rs @@ -18,3 +18,4 @@ pub mod dhcp; pub mod parser; pub mod logger; +pub mod detect; diff --git a/src/Makefile.am b/src/Makefile.am index 23e185a60c..30762104f4 100755 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -296,6 +296,7 @@ noinst_HEADERS = \ detect-snmp-pdu_type.h \ detect-snmp-usm.h \ detect-snmp-version.h \ + detect-dhcp-leasetime.h \ detect-ssh-hassh.h \ detect-ssh-hassh-server.h \ detect-ssh-hassh-server-string.h \ @@ -892,6 +893,7 @@ libsuricata_c_a_SOURCES = \ detect-snmp-pdu_type.c \ detect-snmp-usm.c \ detect-snmp-version.c \ + detect-dhcp-leasetime.c \ detect-ssh-hassh.c \ detect-ssh-hassh-server.c \ detect-ssh-hassh-server-string.c \ diff --git a/src/detect-dhcp-leasetime.c b/src/detect-dhcp-leasetime.c new file mode 100644 index 0000000000..74e25fbde9 --- /dev/null +++ b/src/detect-dhcp-leasetime.c @@ -0,0 +1,130 @@ +/* Copyright (C) 2022 Open Information Security Foundation + * + * You can copy, redistribute or modify this Program under the terms of + * the GNU General Public License leasetime 2 as published by the Free + * Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * leasetime 2 along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ + +#include "suricata-common.h" +#include "rust.h" +#include "detect-dhcp-leasetime.h" +#include "detect-engine.h" +#include "detect-engine-mpm.h" +#include "detect-engine-prefilter.h" +#include "detect-engine-uint.h" +#include "detect-parse.h" + +static int g_buffer_id = 0; + +/** + * \internal + * \brief Function to match leasetime of a TX + * + * \param t Pointer to thread vars. + * \param det_ctx Pointer to the pattern matcher thread. + * \param f Pointer to the current flow. + * \param flags Flags. + * \param state App layer state. + * \param s Pointer to the Signature. + * \param m Pointer to the sigmatch that we will cast into + * DetectU64Data. + * + * \retval 0 no match. + * \retval 1 match. + */ +static int DetectDHCPLeaseTimeMatch(DetectEngineThreadCtx *det_ctx, Flow *f, uint8_t flags, + void *state, void *txv, const Signature *s, const SigMatchCtx *ctx) +{ + SCEnter(); + + uint64_t leasetime; + if (rs_dhcp_tx_get_leasetime(txv, &leasetime)) { + const DetectU64Data *dd = (const DetectU64Data *)ctx; + if (DetectU64Match(leasetime, dd)) { + SCReturnInt(1); + } + } + SCReturnInt(0); +} + +/** + * \internal + * \brief Function to free memory associated with DetectU64Data. + * + * \param de_ptr Pointer to DetectU64Data. + */ +static void DetectDHCPLeaseTimeFree(DetectEngineCtx *de_ctx, void *ptr) +{ + rs_detect_u64_free(ptr); +} + +/** + * \brief Function to add the parsed dhcp leasetime field into the current signature. + * + * \param de_ctx Pointer to the Detection Engine Context. + * \param s Pointer to the Current Signature. + * \param rawstr Pointer to the user provided flags options. + * \param type Defines if this is notBefore or notAfter. + * + * \retval 0 on Success. + * \retval -1 on Failure. + */ +static int DetectDHCPLeaseTimeSetup(DetectEngineCtx *de_ctx, Signature *s, const char *rawstr) +{ + if (DetectSignatureSetAppProto(s, ALPROTO_DHCP) != 0) + return -1; + + DetectU64Data *dd = DetectU64Parse(rawstr); + if (dd == NULL) { + SCLogError(SC_ERR_INVALID_ARGUMENT, "Parsing \'%s\' failed for %s", rawstr, + sigmatch_table[DETECT_AL_DHCP_LEASETIME].name); + return -1; + } + + /* okay so far so good, lets get this into a SigMatch + * and put it in the Signature. */ + SigMatch *sm = SigMatchAlloc(); + if (sm == NULL) + goto error; + + sm->type = DETECT_AL_DHCP_LEASETIME; + sm->ctx = (void *)dd; + + SigMatchAppendSMToList(s, sm, g_buffer_id); + return 0; + +error: + DetectDHCPLeaseTimeFree(de_ctx, dd); + return -1; +} + +/** + * \brief Registration function for dhcp.procedure keyword. + */ +void DetectDHCPLeaseTimeRegister(void) +{ + sigmatch_table[DETECT_AL_DHCP_LEASETIME].name = "dhcp.leasetime"; + sigmatch_table[DETECT_AL_DHCP_LEASETIME].desc = "match DHCP leasetime"; + sigmatch_table[DETECT_AL_DHCP_LEASETIME].url = "/rules/dhcp-keywords.html#dhcp-leasetime"; + sigmatch_table[DETECT_AL_DHCP_LEASETIME].AppLayerTxMatch = DetectDHCPLeaseTimeMatch; + sigmatch_table[DETECT_AL_DHCP_LEASETIME].Setup = DetectDHCPLeaseTimeSetup; + sigmatch_table[DETECT_AL_DHCP_LEASETIME].Free = DetectDHCPLeaseTimeFree; + + DetectAppLayerInspectEngineRegister2("dhcp.leasetime", ALPROTO_DHCP, SIG_FLAG_TOSERVER, 0, + DetectEngineInspectGenericList, NULL); + + DetectAppLayerInspectEngineRegister2("dhcp.leasetime", ALPROTO_DHCP, SIG_FLAG_TOCLIENT, 0, + DetectEngineInspectGenericList, NULL); + + g_buffer_id = DetectBufferTypeGetByName("dhcp.leasetime"); +} diff --git a/src/detect-dhcp-leasetime.h b/src/detect-dhcp-leasetime.h new file mode 100644 index 0000000000..6a9baeb5fa --- /dev/null +++ b/src/detect-dhcp-leasetime.h @@ -0,0 +1,23 @@ +/* Copyright (C) 2022 Open Information Security Foundation + * + * You can copy, redistribute or modify this Program under the terms of + * the GNU General Public License version 2 as published by the Free + * Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * version 2 along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ + +#ifndef __DETECT_DHCP_LEASETIME_H__ +#define __DETECT_DHCP_LEASETIME_H__ + +void DetectDHCPLeaseTimeRegister(void); + +#endif /* __DETECT_DHCP_LEASETIME_H__ */ diff --git a/src/detect-engine-register.c b/src/detect-engine-register.c index 1c9d7a275b..4ad49cc09d 100644 --- a/src/detect-engine-register.c +++ b/src/detect-engine-register.c @@ -200,6 +200,7 @@ #include "detect-rfb-name.h" #include "detect-target.h" #include "detect-template-rust-buffer.h" +#include "detect-dhcp-leasetime.h" #include "detect-snmp-usm.h" #include "detect-snmp-version.h" #include "detect-snmp-community.h" @@ -637,6 +638,7 @@ void SigTableSetup(void) DetectRfbNameRegister(); DetectTargetRegister(); DetectTemplateRustBufferRegister(); + DetectDHCPLeaseTimeRegister(); DetectSNMPUsmRegister(); DetectSNMPVersionRegister(); DetectSNMPCommunityRegister(); diff --git a/src/detect-engine-register.h b/src/detect-engine-register.h index 1451bfbd9c..c6160f5f99 100644 --- a/src/detect-engine-register.h +++ b/src/detect-engine-register.h @@ -268,6 +268,7 @@ enum DetectKeywordId { DETECT_FTPDATA, DETECT_TARGET, DETECT_AL_TEMPLATE_RUST_BUFFER, + DETECT_AL_DHCP_LEASETIME, DETECT_AL_SNMP_USM, DETECT_AL_SNMP_VERSION, DETECT_AL_SNMP_COMMUNITY,