CVE-2015-5361 Junos: FTPS through SRX opens up wide range of data channel TCP ports
Enabling ftps-extensions on Junos SRX allows FTPS clients to access all TCP ports on the server, bypassing firewall restrictions.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2015-5361?
CVE-2015-5361 is a medium-severity vulnerability in Juniper Junos, published on 28 Feb 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Background For regular, unencrypted FTP traffic, the FTP ALG can inspect the unencrypted control channel and open related sessions for the FTP data channel. These related sessions (gates) are specific to source and destination IPs and ports of client and server. The design intent of the ftps-extensions option (which is disabled by default) is to provide similar functionality when the SRX secures the FTP/FTPS client. As the control channel is encrypted, the FTP ALG cannot inspect the port specific information and will open a wider TCP data channel (gate) from client IP to server IP on all destination TCP ports. In FTP/FTPS client environments to an enterprise network or the Internet, this is the desired behavior as it allows firewall policy to be written to FTP/FTPS servers on well-known control ports without using a policy with destination IP ANY and destination port ANY. Issue The ftps-extensions option is not intended or recommended where the SRX secures the FTPS server, as the wide data channel session (gate) will allow the FTPS client temporary access to all TCP ports on the FTPS server. The data session is associated to the control channel and will be closed when the control channel session closes. Depending on the configuration of the FTPS server, supporting load-balancer, and SRX inactivity-timeout values, the server/load-balancer and SRX may keep the control channel open for an extended period of time, allowing an FTPS client access for an equal duration. Note that the ftps-extensions option is not enabled by default.
Weakness: CWE-326
Which versions are affected by CVE-2015-5361?
It affects 1 product.
Products include Juniper Junos.
How do I fix CVE-2015-5361?
No fix has been published for CVE-2015-5361 yet. Limit exposure of the affected software until one is available.
Is CVE-2015-5361 being exploited?
There is no known exploitation of CVE-2015-5361 in the wild and no public exploit code.
Other vulnerabilities in Juniper Junos
- CVE-2023-36845 Juniper Junos OS EX Series and SRX Series PHP External Variable Modification
- CVE-2020-1631 Juniper Junos OS Path Traversal
- CVE-2025-21590 Juniper Junos OS Improper Isolation or Compartmentalization
- CVE-2023-36851 Juniper Junos OS SRX Series Missing Authentication for Critical Function
- CVE-2023-36844 Juniper Junos OS EX Series PHP External Variable Modification
Sources
Also known as GHSA-x6c6-rqqc-c89m.