> For the complete documentation index, see [llms.txt](https://cortex-docs.paloaltonetworks.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://cortex-docs.paloaltonetworks.com/analytics-alerts/alerts-by-name/sender-name-used-by-multiple-addresses-across-multiple-domains.md).
# Sender name used by multiple addresses across multiple domains
### Synopsis
| Field | Value |
| -------------------- | ----------------------- |
| Activation Period | 14 Days |
| Training Period | 30 Days |
| Test Period | 3 Hours |
| Deduplication Period | 1 Day |
| Required Data | Microsoft 365 Emails |
| Detection Modules | Email |
| Detector Tags | Phishing |
| ATT\&CK Tactic | Initial Access (TA0001) |
| ATT\&CK Technique | Phishing (T1566) |
| Severity | Informational |
### Description
A single sender display name was observed over a short time period across multiple distinct sender email addresses spanning multiple sender FQDNs. This pattern of address rotation under a stable display name is uncommon and may suggest automated sending behavior.
### Attacker's Goals
Impersonate a trusted identity by reusing a recognizable display name while distributing sending across multiple domains, so no single domain's reputation is degraded enough to trigger domain-scoped defenses.
### Investigative actions
* Examine the sender's IP address and reputation.
* Verify whether the sender's IP address has appeared in different log sources before, and if it is recognizable.
* If the message contains attachments or links, scrutinize them for any suspicious indications.
* Monitor further actions taken, such as file downloads or access to potentially malicious links.
### Variations
Rapid high-volume sender name reuse (multiple domains)
**Synopsis**
| Field | Value |
| ----------------- | ----------------------- |
| ATT\&CK Tactic | Initial Access (TA0001) |
| ATT\&CK Technique | Phishing (T1566) |
| Severity | Informational |
**Description**
A single sender display name was observed across a large number of distinct sender email addresses spanning multiple sender FQDNs within a very short time window. The combination of cross-domain distribution, high address cardinality, and rapid sender identity reuse strongly suggests automated sending patterns.
**Attacker's Goals**
Impersonate a trusted identity by reusing a recognizable display name while distributing sending across multiple domains, so no single domain's reputation is degraded enough to trigger domain-scoped defenses.
**Investigative actions**
* Examine the sender's IP address and reputation.
* Verify whether the sender's IP address has appeared in different log sources before, and if it is recognizable.
* If the message contains attachments or links, scrutinize them for any suspicious indications.
* Monitor further actions taken, such as file downloads or access to potentially malicious links.
Rapid sender name reuse (multiple domains)
**Synopsis**
| Field | Value |
| ----------------- | ----------------------- |
| ATT\&CK Tactic | Initial Access (TA0001) |
| ATT\&CK Technique | Phishing (T1566) |
| Severity | Informational |
**Description**
A single sender display name was observed across multiple distinct sender email addresses spanning multiple sender FQDNs within a short time window The combination of cross-domain distribution and rapid sender identity reuse may suggest an automated sending pattern.
**Attacker's Goals**
Impersonate a trusted identity by reusing a recognizable display name while distributing sending across multiple domains, so no single domain's reputation is degraded enough to trigger domain-scoped defenses.
**Investigative actions**
* Examine the sender's IP address and reputation.
* Verify whether the sender's IP address has appeared in different log sources before, and if it is recognizable.
* If the message contains attachments or links, scrutinize them for any suspicious indications.
* Monitor further actions taken, such as file downloads or access to potentially malicious links.
High-volume sender name reuse (multiple domains)
**Synopsis**
| Field | Value |
| ----------------- | ----------------------- |
| ATT\&CK Tactic | Initial Access (TA0001) |
| ATT\&CK Technique | Phishing (T1566) |
| Severity | Informational |
**Description**
A single sender display name was observed across a large number of distinct sender email addresses spanning multiple sender FQDNs. High address cardinality across multiple domains under a consistent display name is suspicious, and may indicate automated behavior used for evasion or scaling.
**Attacker's Goals**
Impersonate a trusted identity by reusing a recognizable display name while distributing sending across multiple domains, so no single domain's reputation is degraded enough to trigger domain-scoped defenses.
**Investigative actions**
* Examine the sender's IP address and reputation.
* Verify whether the sender's IP address has appeared in different log sources before, and if it is recognizable.
* If the message contains attachments or links, scrutinize them for any suspicious indications.
* Monitor further actions taken, such as file downloads or access to potentially malicious links.
---
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