Query: Sigma rule for Detects remote RPC calls to possibly abuse remote encryption service via MS-EFSR
Matching passage: Sigma rule: Detects remote RPC calls to possibly abuse remote encryption service via MS-EFSR. Logsource: rpc_firewall / application. Rule: title: Remote Server Service Abuse for Lateral Movement id: 10018e73-06ec-46ec-8107-9172f1e04ff2 status: test description: Detects remote RPC calls to possibly abuse remote encryption service via MS-EFSR references: - https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-srvs/accf23b0-0f57-441c-9185-43041f1b0ee9 - https://github.com/jsecurity101/MSRPC-to-ATTACK/blob/ddd4608fe8684fcf2fcf9b48c5f0b3c28097f8a3/documents/MS-SCMR.md - https://github.com/zeronetworks/rpcfirewall - https://zeronetworks.com/blog/stopping-lateral-movement-via-the-rpc-firewall/ author: Sagie Dulce, Dekel Paz date: 2022-01-01 tags: - attack.lateral-movement - attack.execution - attack.t1569.002 logsource: product: rpc_firewall category: application definition: 'Requirements: install and apply the RPC Firewall to all processes with "audit:true action:block uuid:367abb81-9844-35f1-ad32-98f038001003' detection: selection: EventLog: RPCFW EventID: 3 InterfaceUuid: 367abb81-9844-35f1-ad32-98f038001003 condition: selection falsepositives: - Administrative tasks on remote services level: high
Near-miss passage: Sigma rule: The DNS Z flag is bit within the DNS protocol header that is, per the IETF design, meant to be used reserved (unused). A. Logsource: zeek / dns. Rule: title: Suspicious DNS Z Flag Bit Set id: ede05abc-2c9e-4624-9944-9ff17fdc0bf5 status: test description: 'The DNS Z flag is bit within the DNS protocol header that is, per the IETF design, meant to be used reserved (unused). Although recently it has been used in DNSSec, the value being set to anything other than 0 should be rare. Otherwise if it is set to non 0 and DNSSec is being used, then excluding the legitimate domains is low effort and high reward. Determine if multiple of these files were accessed in a short period of time to further enhance the possibility of seeing if this was a one off or the possibility of larger sensitive file gathering. This Sigma query is designed to accompany the Corelight Threat Hunting Guide, which can be found here: https://www3.corelight.com/corelights-introductory-guide-to-threat-hunting-with-zeek-bro-logs'' ' references: - https://twitter.com/neu5ron/status/1346245602502443009 - https://tdm.socprime.com/tdm/info/eLbyj4JjI15v#sigma - https://tools.ietf.org/html/rfc2929#section-2.1 - https://www.netresec.com/?page=Blog&month=2021-01&post=Finding-Targeted-SUNBURST-Victims-with-pDNS author: '@neu5ron, SOC Prime Team, Corelight' date: 2021-05-04 modified: 2022-11-29 tags: - attack.t1095 - attack.t1571 - attack.command-and-control logsource: product: zeek service: dns detection: z_flag_unset: Z: 0 most_probable_valid_domain: query|contains: . exclude_tlds: query|endswith: - .arpa - .local - .ultradns.net - .twtrdns.net - .azuredns-prd.info - .azure-dns.com - .azuredns-ff.info - .azuredns-ff.org - .azuregov-dns.org exclude_query_types: qtype_name: - ns - mx exclude_responses: answers|endswith: \\x00 exclude_netbios: id.resp_p: - 137 - 138 - 139 condition: not z_flag_unset and most_probable_valid_domain and not (exclude_tlds or exclude_query_types or exclude_responses or exclude_netbios) falsepositives: - Internal or legitimate external domains using DNSSec. Verify if these are legitimate DNSSec domains and then exclude them. - If you work in a Public Sector then it may be good to exclude things like endswith ".edu", ".gov" and or ".mil" level: medium