Suspicious DNS Query Indicating Kerberos Coercion via DNS Object SPN Spoofing - Network
Detects DNS queries containing patterns associated with Kerberos coercion attacks via DNS object spoofing. The pattern "1UWhRCAAAAA..BAAAA" is a base64-encoded signature that corresponds to a marshaled CREDENTIAL_TARGET_INFORMATION structure. Attackers can use this technique to coerce authentication from victim systems to attacker-controlled hosts. It is one of the strong indicators of a Kerberos coercion attack, where adversaries manipulate DNS records to spoof Service Principal Names (SPNs) and redirect authentication requests like CVE-2025-33073.
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Open this Sigma rule in the converter with the YAML preloaded and ready for backend selection.
detection:
selection:
query|contains|all:
- 'UWhRCA' # Follows this pattern UWhRCAAAAA..BAAA
- 'BAAAA'
condition: selectionFalse positive likelihood has not been assessed. Additional context may be needed during triage.
Potential Kerberos Coercion by Spoofing SPNs via DNS Manipulation
Detects modifications to DNS records in Active Directory where the Distinguished Name (DN) contains a base64-encoded blob matching the pattern "1UWhRCAAAAA...BAAAA". This pattern corresponds to a marshaled CREDENTIAL_TARGET_INFORMATION structure, commonly used in Kerberos coercion attacks. Adversaries may exploit this to coerce victim systems into authenticating to attacker-controlled hosts by spoofing SPNs via DNS. It is one of the strong indicators of a Kerberos coercion attack,. where adversaries manipulate DNS records to spoof Service Principal Names (SPNs) and redirect authentication requests like CVE-2025-33073. Please investigate the user account that made the changes, as it is likely a low-privileged account that has been compromised.
Detects similar activity. Both rules may fire on overlapping events.
Suspicious DNS Query Indicating Kerberos Coercion via DNS Object SPN Spoofing
Detects DNS queries containing patterns associated with Kerberos coercion attacks via DNS object spoofing. The pattern "1UWhRCAAAAA..BAAAA" is a base64-encoded signature that corresponds to a marshaled CREDENTIAL_TARGET_INFORMATION structure. Attackers can use this technique to coerce authentication from victim systems to attacker-controlled hosts. It is one of the strong indicators of a Kerberos coercion attack, where adversaries manipulate DNS records to spoof Service Principal Names (SPNs) and redirect authentication requests like CVE-2025-33073.
Detects similar activity. Both rules may fire on overlapping events.