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@ -83,6 +83,13 @@ no program listening on that divert socket or the program does not reinject the
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packets into the kernel, the connection is effectively blocked. In the case of
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SSLproxy, SSLproxy acts as both the packet filter and the kernel, and the
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communication occurs over networking sockets.
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.LP
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SSLproxy does not automagically redirect any network traffic. To actually
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implement a proxy, you also need to redirect the traffic to the system
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running \fBsslproxy\fP. Your options include running \fBsslproxy\fP on a
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legitimate router, ARP spoofing, ND spoofing, DNS poisoning, deploying a rogue
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access point (e.g. using hostap mode), physical recabling, malicious VLAN
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reconfiguration or route injection, /etc/hosts modification and so on.
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.SH Proxy specification
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For example, given the following proxy specification:
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.LP
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@ -90,12 +97,14 @@ https 127.0.0.1 8443 up:8080
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.LP
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SSLproxy listens for HTTPS connections on 127.0.0.1:8443. Upon receiving a
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connection from the Client, it decrypts and diverts the packets to a Program
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listening on 127.0.0.1:8080. After processing the packets, the Program gives
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them back to SSLproxy listening on a dynamically assigned address, which the
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Program obtains from the SSLproxy line in the first packet in the connection.
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Then SSLproxy re-encrypts and sends the packets to the Server. The response
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from the Server follows the same path to the Client in reverse
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order.
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listening on 127.0.0.1:8080. The default divert address is 127.0.0.1, which
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can be configured by the ua option. After processing the packets, the Program
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gives them back to SSLproxy listening on a dynamically assigned address, which
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the Program obtains from the SSLproxy line in the first packet in the
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connection. Then SSLproxy re-encrypts and sends the packets to the Server.
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.LP
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The response from the Server follows the same path back to the Client in
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reverse order.
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.SH SSLproxy line
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A sample line SSLproxy inserts into the first packet in the connection is the
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following:
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@ -106,12 +115,12 @@ The first IP:port pair is a dynamically assigned address that SSLproxy expects
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the program send the packets back to it. The second and third IP:port pairs
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are the actual source and destination addresses of the connection
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respectively. Since the program receives the packets from SSLproxy, it cannot
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determine the source and destination addresses of the packets by itself, hence
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must rely on the information in this SSLproxy line. The last letter is either
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s or p, for SSL/TLS encrypted or plain traffic respectively. This information
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is also important for the program, because it cannot reliably determine if the
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actual network traffic it is processing was encrypted or not
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before being diverted to it.
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determine the source and destination addresses of the packets by itself, e.g
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by asking the NAT engine, hence must rely on the information in the SSLproxy
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line. The last letter is either s or p, for SSL/TLS encrypted or plain traffic
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respectively. This information is also important for the program, because it
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cannot reliably determine if the actual network traffic it is processing was
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encrypted or not before being diverted to it.
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.SH Listening program
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The program that packets are diverted to should support this mode of operation.
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Specifically, it should be able to recognize the SSLproxy address in the first
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@ -131,10 +140,11 @@ specification:
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https 127.0.0.1 8443 up:8080 ua:192.168.0.1 ra:192.168.1.1
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.LP
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The ua option instructs SSLproxy to divert packets to 192.168.0.1:8080,
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instead of 127.0.0.1:8080 as in the previous example. Also, the ra option
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instructs SSLproxy to listen for returned packets from the program on
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192.168.1.1. Accordingly, the line SSLproxy inserts into the first packet in
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the connection now becomes:
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instead of 127.0.0.1:8080 as in the previous proxyspec example. Also, the ra
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option instructs SSLproxy to listen for returned packets from the program on
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192.168.1.1, instead of 127.0.0.1 as in the previous SSLproxy line.
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.LP
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Accordingly, the SSLproxy line now becomes:
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.LP
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SSLproxy: [192.168.1.1]:34649,[192.168.3.24]:47286,[192.168.111.130]:443,s
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.LP
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@ -151,6 +161,14 @@ SSLproxy supports SSL 3.0, TLS 1.0, TLS 1.1, TLS 1.2, and TLS 1.3, and
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optionally SSL 2.0 as well. SSLproxy supports Server Name Indication (SNI),
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but not Encrypted SNI in TLS 1.3. It is able to work with RSA, DSA and ECDSA
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keys and DHE and ECDHE cipher suites.
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.LP
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The following features of SSLproxy are IPv4 only:
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- Divert addresses for listening programs in proxyspecs
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- SSLproxy return addresses dynamically assigned to connections
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- IP addresses in the ua and ra options
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- IP and ethernet addresses of clients in user authentication
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- Target IP and ethernet addresses in mirror logging
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.LP
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.SH OCSP, HPKP, HSTS, Upgrade et al.
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SSLproxy implements a number of defences against mechanisms which would
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normally prevent MitM attacks or make them more difficult. SSLproxy can deny
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@ -190,7 +208,8 @@ SSLproxy verifies upstream certificates by default. If the verification fails,
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the connection is terminated immediately. This is in contrast to SSLsplit,
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because in order to maximize the chances that a connection can be successfully
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split, SSLsplit accepts all certificates by default, including self-signed
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ones.
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ones. See the risks of SSL inspection for the reasons of this difference. You
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can disable this feature by the VerifyPeer option.
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.SH Client certificates
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SSLproxy uses the certificate and key from the pemfiles configured by the
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ClientCert and ClientKey options when the destination requests client
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@ -215,7 +234,7 @@ CREATE TABLE USERS(
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);
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.LP
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SSLproxy does not create this users table or the database file by itself, nor
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does it log users in or out. So the database file and this table should
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does it log users in or out. So the database file and the users table should
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already exist at the location pointed to by the UserDBPath option. An external
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program should log users in and out on the users table. The external program
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should fill out all the fields in user records, except perhaps for the DESC
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@ -256,17 +275,20 @@ listening programs.
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- Connections from users in DivertUsers, if defined, are diverted to listening
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programs.
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- Connections from users in PassUsers, if defined, are simply passed through
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to their original destinations.
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- Users not listed in DivertUsers or PassUsers are blocked.
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- If no DivertUsers list is defined, only users *not* listed in PassUsers are
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diverted to listening programs.
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to their original destinations. SSLproxy engages the Passthrough mode for that
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purpose.
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- If both DivertUsers and PassUsers are defined, users not listed in either of
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the lists are blocked. SSLproxy simply terminates their connections.
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- If *no* DivertUsers list is defined, only users *not* listed in PassUsers
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are diverted to listening programs.
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.LP
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These user control lists can be defined globally or per-proxyspec.
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.SH Servers Excluded from SSL Inspection
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.SH Excluding sites from SSL inspection
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PassSite option allows certain SSL sites to be excluded from SSL inspection.
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If a PassSite matches SNI or common names in the SSL certificate, the
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connection is passed through the proxy without being diverted to the listening
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program. For example, sites requiring client authentication can be added as
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If a PassSite matches the SNI or common names in the SSL certificate of a
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connection, that connection is passed through the proxy without being diverted
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to the listening program. SSLproxy engages the Passthrough mode for that
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purpose. For example, sites requiring client authentication can be added as
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PassSite.
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.LP
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Per-site filters can be defined using client IP addresses, users, and
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@ -278,13 +300,6 @@ Logging options include traditional SSLproxy connect and content log files as
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well as PCAP files and mirroring decrypted traffic to a network interface.
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Additionally, certificates, master secrets and local process information can be
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logged.
|
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.LP
|
|
|
|
|
SSLproxy does not automagically redirect any network traffic. To actually
|
|
|
|
|
implement a proxy, you also need to redirect the traffic to the system
|
|
|
|
|
running \fBsslproxy\fP. Your options include running \fBsslproxy\fP on a
|
|
|
|
|
legitimate router, ARP spoofing, ND spoofing, DNS poisoning, deploying a rogue
|
|
|
|
|
access point (e.g. using hostap mode), physical recabling, malicious VLAN
|
|
|
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reconfiguration or route injection, /etc/hosts modification and so on.
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.SH OPTIONS
|
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.TP
|
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.B \-a \fIpemfile\fP
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Soner Tari
3 years ago