Rules: Possible DNS Data Exfiltration
Some families of malware use data nested within the subdomain portion of a DNS query as a means of data exfiltration. This can be identified by looking for DNS queries where the full query is substantially longer than the top-level domain (e.g., ooo.nu6tgnzvgm2tmmbzgq4a.rkgotw5.5z5i6fjnugmxfowy.beevish.com is substantially longer than beevish.com). This technique is described in https://attack.mitre.org/techniques/T1001/.
| Detail | Value |
|---|---|
| Type | Match |
| Category | Exfiltration |
| Apply Risk to Entities | device_hostname, device_ip, srcDevice_hostname, srcDevice_ip, user_username |
| Signal Name | Possible DNS Data Exfiltration |
| Summary Expression | Possible DNS data exfiltration from IP: {{srcDevice_ip}} to IP: {{dstDevice_ip}} |
| Score/Severity | Static: 3 |
| Enabled by Default | True |
| Prototype | False |
| Tags | _mitreAttackTactic:TA0010, _mitreAttackTechnique:T1048, _mitreAttackTechnique:T1048.003 |
- Amazon AWS - Route53
- Bro - Bro
- Cisco Systems - Umbrella
- CrowdStrike - FDR
- Fortinet - Fortigate
- ISC - Bind
- Infoblox - Network Identity Operating System
- Microsoft - DNS
- Microsoft - Windows
- Netskope - WebTx
- Zscaler - Firewall
- Zscaler - Nanolog Streaming Service
| Origin | Field |
|---|---|
| Normalized Schema | device_hostname |
| Normalized Schema | device_ip |
| Normalized Schema | dns_queryDomain |
| Normalized Schema | dns_queryDomain_alexaRank |
| Normalized Schema | listMatches |
| Normalized Schema | srcDevice_hostname |
| Normalized Schema | srcDevice_ip |
| Normalized Schema | user_username |