Netgate pfSense CE 2.7.1 through 2.9.0 contains a reflected cross-site scripting vulnerability in firewallrules.php that allows remote attackers to inject script via the unencoded if parameter. When the non-default Require Firewall Interface option is enabled, attackers can lure users with firewall rules privileges into opening a crafted GET link to execute script in the WebGUI with their privileges.

Netgate pfSense CE 2.3.0 through 2.9.0 contains a stored cross-site scripting vulnerability that allows authenticated users with Firewall: Rules or NAT: Port Forward privileges to inject scripts via the separator color field. Attackers can submit a crafted separator[] color value that displayseparator() renders unencoded into class attributes, executing in administrators' browsers to perform WebGUI actions with their privileges.

Netgate pfSense CE through 2.9.0 contains an authorization bypass vulnerability that allows read-only WebGUI users to replace config.xml because configrestore() and configinstall() ignore the 'User - Config: Deny Config Write' privilege. Attackers holding page privileges for servicesacb.php, uploadconfig.php, diagconfbak.php, or diagbackup.php can install a chosen config.xml to gain root-level code execution after reload or reboot.

pfSense CE 2.7.0 through 2.9.0 contains a command injection vulnerability in servicescaptiveportalhasync.php that allows users with only the Captive Portal HA privilege to execute commands as root. Attackers can set backwardsyncip to a malicious XMLRPC server returning connectedusers with shell metacharacters in ip or mac fields, which captiveportalloadpfctl passes unescaped to a pfctl shell command.

Netgate pfSense CE through 2.9.0 contains a local file read vulnerability that allows users with the Dynamic DNS client privilege to read files as root by setting a file:// custom Update URL in servicesdyndnsedit.php. Attackers can set a non-matching Result Match string so checkStatus() logs file contents such as /conf/config.xml or /etc/master.passwd to the system log.

Netgate pfSense CE from 2.7.1 through 2.9.0 contains a CRLF injection vulnerability in servicesunboundadvanced.php that allows authenticated users with DNS Resolver: Advanced privilege to inject Unbound directives. Attackers can embed CR/LF characters in the unvalidated sockqueuetimeout parameter, which is written raw into unbound.conf, to override local records and forwarding for all clients.

Netgate pfSense CE through 2.9.0 contains a CRLF injection vulnerability in servicesunboundacls.php that allows authenticated users with the DNS Resolver: Access Lists privilege to inject Unbound configuration directives. Attackers can embed CR/LF characters in the aclname or aclaction fields written to accesslists.conf to add local-data, local-zone, or forward-zone directives and control DNS answers served to LAN clients.

pfSense CE 2.4.5 through 2.9.0 contains an OS command injection vulnerability that allows authenticated WebGUI users with Advanced Admin Access privilege to execute commands as root via Login Protection settings. Attackers can submit sshguard threshold, block time, or detection time values containing newlines or $(...) that are written unvalidated to sshguard.conf and sourced as root on restart.

Netgate pfSense CE 2.5.0 through 2.9.0 contains an OS command injection vulnerability in openvpn.learn-address.sh that allows authenticated VPN clients to execute commands as the unbound user. Attackers can embed shell metacharacters in the certificate common name or username, which is interpolated unquoted into su -c strings, when DNS Resolver client registration is enabled.

pfSense CE through 2.9.0 contains an OS command injection vulnerability in the OpenVPN openvpn.connectasync.sh script that allows authenticated VPN users to execute commands as root via crafted usernames. Attackers authenticated through RADIUS or LDAP can use usernames containing single quotes and shell metacharacters to break out of the eval'd pfctl anchor name on connect or disconnect.

Netgate pfSense CE 2.7.0 through 2.9.0 contains a configuration injection vulnerability that allows authenticated users with IPsec Mobile privileges to execute commands as root via the loginbanner field. Attackers can submit a single-line banner containing '}' to escape the unquoted strongswan.conf attr value and define charon.start-scripts entries that charon executes as root on restart.

Netgate pfSense CE through 2.9.0 contains a php.ini injection vulnerability that allows authenticated users with General Setup privileges to inject directives by submitting an unvalidated timezone value. Attackers can embed a quote and newline to add autoprependfile pointing at /var/db/zoneinfo, executing PHP as root after php.ini is regenerated at boot or php-fpm restart.

pfSense CE through 2.9.0 contains a crontab injection vulnerability in interfacespppsedit.php that allows authenticated users to execute commands as root by injecting newlines into the ptpid or reset hour/minute fields. Attackers holding the 'WebCfg - Interfaces: PPPs: Edit' privilege can submit crafted POST values that configurecron() writes unescaped into /etc/crontab, running arbitrary root commands on schedule.

Netgate pfSense CE through 2.9.0 contains a configuration injection vulnerability that allows authenticated WebGUI users to inject mpd5 commands by submitting an unescaped RADIUS shared secret. Attackers with L2TP or PPPoE Server edit privileges can POST a secret containing a quote and newline to vpnl2tp.php or servicespppoeedit.php, appending an up-script that executes as root when a session starts.

Netgate pfSense CE through 2.9.0 contains a newline injection vulnerability in servicespppoeedit.php that allows privileged users to inject mpd.secret entries via unvalidated username POST fields. Attackers with the PPPoE Server Edit privilege can add a line whose secret begins with '!', making mpd5 run commands as root when a PPPoE client authenticates.

Netgate pfSense CE 2.7.0 through 2.9.0 contains an OS command injection vulnerability that allows authenticated users with Traffic Shaper Limiters privileges to execute root commands by tampering with the limiter number field. Attackers can submit a malicious hidden 'number' value when editing a limiter, then delete it so deletequeue() passes the unquoted value to dnctl via /bin/sh as root.

Netgate pfSense CE through 2.9.0 contains an OS command injection vulnerability that allows authenticated users with Virtual IP edit privileges to execute commands as root by storing an unvalidated CARP VHID. Attackers can supply a VHID containing shell metacharacters that executes via interfaceipaliasconfigure() ifconfig calls or getcarpinterfacestatus() when CARP status is rendered.

Netgate pfSense CE through 2.9.0 contains an OS command injection vulnerability that allows authenticated users with gateway edit privileges to execute commands as root by injecting shell metacharacters into an IPv6 link-local zone index. Attackers can set a gateway Monitor IP whose unvalidated zone carries a payload, which startdpinger() passes unescaped to the dpinger shell command when monitoring is applied.

Netgate pfSense CE 2.7.0 through 2.9.0 contains an OS command injection vulnerability that allows authenticated users with QinQ edit privilege to run commands by storing an unvalidated parent interface name. Attackers can save a crafted 'if' value, then edit the QinQ entry so it is interpolated into ifconfig shell commands, executing commands as root.

Netgate pfSense CE through 2.9.0 contains an OS command injection vulnerability that allows authenticated users to execute commands as root by supplying a crafted wireless parent interface name. Attackers with limited Wireless Edit or Interface Assignments privileges can submit values like ath0;<cmd> via interfaceswirelessedit.php or interfacesassign.php, which interfacewirelessclone() interpolates unescaped into an ifconfig shell command.

In Netgate pfSense Plus before 26.07 and pfSense CE before 2.9.0, a Local File Inclusion (LFI) vulnerability in the Dashboard (index.php) widget sequence data handling allows an authenticated attacker to execute arbitrary PHP code. To exploit this, an attacker with privileges to modify Dashboard settings and write arbitrary files to the pfSense firewall system (e.g., /tmp/test.widget.php) can submit a crafted widget sequence value containing a path traversal payload (e.g., ../../../../../../../../../../../tmp/test). The Dashboard will subsequently read and execute the arbitrary PHP file as if it were a standard widget.

Cross-Site Scripting (XSS) vulnerability in the RSS Widget of Netgate pfSense Plus (versions 26.03, 25.11.1) and pfSense CE (version 2.8.1) allows remote authenticated attackers to inject arbitrary JavaScript via malicious content in an RSS feed title. The injected script executes in the browser of any authenticated user who views the dashboard, due to insufficient sanitization of feed title data before rendering in the widget.

pfSense Plus before 26.07 and pfSense CE through 2.8.1 contain a stored cross-site scripting vulnerability in the Traffic Graphs top-talkers feature, where PTR records returned by reverse DNS lookups are incorporated without sanitization into AJAX responses and rendered as HTML through a DOM sink in the administrator interface. An attacker who controls a PTR record and generates sufficient traffic to appear as a top talker can execute arbitrary JavaScript in an administrator's browser, gaining access to the authenticated session context and same-origin access to the firewall management interface, enabling account creation and arbitrary OS command execution.

Netgate pfSense CE 2.8.0 allows code execution in the XMLRPC API via pfsense.execphp. NOTE: the Supplier disputes this because the API call is only available to admins and they are intentionally allowed to execute PHP code.

Netgate pfSense CE 2.7.2 allows code execution by using the module installer with a backup file with a serialized PHP object containing the postrebootcommands property. NOTE: the Supplier disputes this because this installer is only available to admins and they are intentionally allowed to execute PHP code.

Netgate pfSense CE Suricata Path Traversal Remote Code Execution Vulnerability. This vulnerability allows remote attackers to create arbitrary files on affected installations of Netgate pfSense. Authentication is required to exploit this vulnerability.

The specific flaw exists within the Suricata package. The issue results from the lack of proper validation of a user-supplied path prior to using it in file operations. An attacker can leverage this vulnerability to create files in the context of root. Was ZDI-CAN-28085.

In pfSense CE /usr/local/www/snort/snortipreputation.php, the value of the iplist parameter is not sanitized of directory traversal-related characters/strings before being used to check if a file exists. While the contents of the file cannot be read, the server reveals whether a file exists, which allows an attacker to enumerate files on the target. The attacker must be authenticated with at least "WebCfg - Services: Snort package" permissions.

Netgate pfSense CE (prior to 2.8.0 beta release) and corresponding Plus builds is vulnerable to Cross-site scripting (XSS) in the Automatic Configuration Backup (ACB) service, allowing remote attackers to execute arbitrary JavaScript, delete backups, or leak sensitive information via an unsanitized "reason" field and a derivable device key generated from the public SSH key.

Summary

Terrapin is a prefix truncation attack targeting the SSH protocol. More precisely, Terrapin breaks the integrity of SSH's secure channel. By carefully adjusting the sequence numbers during the handshake, an attacker can remove an arbitrary amount of messages sent by the client or server at the beginning of the secure channel without the client or server noticing it.

Mitigations

To mitigate this protocol vulnerability, OpenSSH suggested a so-called "strict kex" which alters the SSH handshake to ensure a Man-in-the-Middle attacker cannot introduce unauthenticated messages as well as convey sequence number manipulation across handshakes.

Warning: To take effect, both the client and server must support this countermeasure.

As a stop-gap measure, peers may also (temporarily) disable the affected algorithms and use unaffected alternatives like AES-GCM instead until patches are available.

Details

The SSH specifications of ChaCha20-Poly1305 (chacha20-poly1305@openssh.com) and Encrypt-then-MAC (-etm@openssh.com MACs) are vulnerable against an arbitrary prefix truncation attack (a.k.a. Terrapin attack). This allows for an extension negotiation downgrade by stripping the SSHMSGEXTINFO sent after the first message after SSHMSGNEWKEYS, downgrading security, and disabling attack countermeasures in some versions of OpenSSH. When targeting Encrypt-then-MAC, this attack requires the use of a CBC cipher to be practically exploitable due to the internal workings of the cipher mode. Additionally, this novel attack technique can be used to exploit previously unexploitable implementation flaws in a Man-in-the-Middle scenario.

The attack works by an attacker injecting an arbitrary number of SSHMSGIGNORE messages during the initial key exchange and consequently removing the same number of messages just after the initial key exchange has concluded. This is possible due to missing authentication of the excess SSHMSGIGNORE messages and the fact that the implicit sequence numbers used within the SSH protocol are only checked after the initial key exchange.

In the case of ChaCha20-Poly1305, the attack is guaranteed to work on every connection as this cipher does not maintain an internal state other than the message's sequence number. In the case of Encrypt-Then-MAC, practical exploitation requires the use of a CBC cipher; while theoretical integrity is broken for all ciphers when using this mode, message processing will fail at the application layer for CTR and stream ciphers.

For more details see https://terrapin-attack.com.

Impact

This attack targets the specification of ChaCha20-Poly1305 (chacha20-poly1305@openssh.com) and Encrypt-then-MAC (-etm@openssh.com), which are widely adopted by well-known SSH implementations and can be considered de-facto standard. These algorithms can be practically exploited; however, in the case of Encrypt-Then-MAC, we additionally require the use of a CBC cipher. As a consequence, this attack works against all well-behaving SSH implementations supporting either of those algorithms and can be used to downgrade (but not fully strip) connection security in case SSH extension negotiation (RFC8308) is supported. The attack may also enable attackers to exploit certain implementation flaws in a man-in-the-middle (MitM) scenario.