Just in case you need need yet another reason to utilize passive DNS analytic, a new significant vulnerability is out for GLIBC. Have stream? You can monitor your queries for this IOC
Update: the attack requires both A and AAAA records. Only show possible attacks with both involved. This should return zero results. If results are returned there “may” be something of interest drill into the answers involved to determine if they are malicious based on the CVE above.
index=streams sourcetype=stream:dns (query_type=A OR query_type=AAAA)
search index=streams sourcetype=stream:dns (query_type=A OR query_type=AAAA)
| rare limit=20 dest
| fields + dest | format
| stats max(bytes_in) max(bytes_out) max(bytes) values(query_type) as qt by src,dest,query
| where mvcount(qt)>=2
| sort – max*
| lookup domain_segments_lookup domain as query OUTPUT privatesuffix as domain
| lookup alexa_lookup_by_str domain OUTPUT rank
| where isnull(rank)
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