> 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/uncommon-reverse-ssh-tunnel-to-external-domain-ip.md).
# Uncommon reverse SSH tunnel to external domain/ip
### Synopsis
| Field | Value |
| -------------------- | -------------------------------- |
| Activation Period | 14 Days |
| Training Period | 30 Days |
| Test Period | N/A (single event) |
| Deduplication Period | 1 Day |
| Required Data | XDR Agent |
| Detector Tags | Abnormal Communication Analytics |
| ATT\&CK Tactic | Command and Control (TA0011) |
| ATT\&CK Technique | Protocol Tunneling (T1572) |
| Severity | Low |
### Description
An uncommon reverse SSH tunnel might have been created.
### Attacker's Goals
Attackers may use SSH to create an encrypted tunnel to allow an attacker to covertly connect to an internal host.
### Investigative actions
* Review the external ip/domain.
* Investigate the causality of the process.
### Variations
Uncommon reverse SOCKS proxy SSH tunnel to external domain/ip
**Synopsis**
| Field | Value |
| ----------------- | ---------------------------- |
| ATT\&CK Tactic | Command and Control (TA0011) |
| ATT\&CK Technique | Protocol Tunneling (T1572) |
| Severity | Medium |
**Description**
An uncommon reverse SSH tunnel might have been created.
**Attacker's Goals**
Attackers may use SSH to create an encrypted tunnel to allow an attacker to covertly connect to an internal host.
**Investigative actions**
* Review the external ip/domain.
* Investigate the causality of the process.
Uncommon reverse SSH tunnel to external domain/ip to a sensitive port via a non-default bind port
**Synopsis**
| Field | Value |
| ----------------- | ---------------------------- |
| ATT\&CK Tactic | Command and Control (TA0011) |
| ATT\&CK Technique | Protocol Tunneling (T1572) |
| Severity | Medium |
**Description**
An uncommon reverse SSH tunnel might have been created.
**Attacker's Goals**
Attackers may use SSH to create an encrypted tunnel to allow an attacker to covertly connect to an internal host.
**Investigative actions**
* Review the external ip/domain.
* Investigate the causality of the process.
Uncommon reverse SSH tunnel to external domain/ip using a sensitive port
**Synopsis**
| Field | Value |
| ----------------- | ---------------------------- |
| ATT\&CK Tactic | Command and Control (TA0011) |
| ATT\&CK Technique | Protocol Tunneling (T1572) |
| Severity | Low |
**Description**
An uncommon reverse SSH tunnel might have been created.
**Attacker's Goals**
Attackers may use SSH to create an encrypted tunnel to allow an attacker to covertly connect to an internal host.
**Investigative actions**
* Review the external ip/domain.
* Investigate the causality of the process.
---
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