Merged revisions 371999,372020 via svnmerge from

file:///srv/subversion/repos/asterisk/branches/10

................
  r371999 | mjordan | 2012-08-30 11:06:47 -0500 (Thu, 30 Aug 2012) | 36 lines

  AST-2012-012: Resolve AMI User Unauthorized Shell Access through ExternalIVR

  The AMI Originate action can allow a remote user to specify information that can
  be used to execute shell commands on the system hosting Asterisk. This can
  result in an unwanted escalation of permissions, as the Originate action, which
  requires the "originate" class authorization, can be used to perform actions
  that would typically require the "system" class authorization. Previous attempts
  to prevent this permission escalation (AST-2011-006, AST-2012-004) have sought
  to do so by inspecting the names of applications and functions passed in with
  the Originate action and, if those applications/functions matched a predefined
  set of values, rejecting the command if the user lacked the "system" class
  authorization. As reported by IBM X-Force Research, the "ExternalIVR"
  application is not listed in the predefined set of values. The solution for
  this particular vulnerability is to include the "ExternalIVR" application in the
  set of defined applications/functions that require "system" class authorization.

  Unfortunately, the approach of inspecting fields in the Originate action against
  known applications/functions has a significant flaw. The predefined set of
  values can be bypassed by creative use of the Originate action or by certain
  dialplan configurations, which is beyond the ability of Asterisk to analyze at
  run-time. Attempting to work around these scenarios would result in severely
  restricting the applications or functions and prevent their usage for legitimate
  means. As such, any additional security vulnerabilities, where an
  application/function that would normally require the "system" class
  authorization can be executed by users with the "originate" class authorization,
  will not be addressed. Instead, the README-SERIOUSLY.bestpractices.txt file has
  been updated to reflect that the AMI Originate action can result in commands
  requiring the "system" class authorization to be executed. Proper system
  configuration can limit the impact of such scenarios.

  (closes issue ASTERISK-20132)
  Reported by: Zubair Ashraf of IBM X-Force Research
  ........

  Merged revisions 371998 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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  r372020 | mjordan | 2012-08-30 11:22:54 -0500 (Thu, 30 Aug 2012) | 17 lines

  AST-2012-013: Resolve ACL rules being ignored during calls by some IAX2 peers

  When an IAX2 call is made using the credentials of a peer defined in a dynamic
  Asterisk Realtime Architecture (ARA) backend, the ACL rules for that peer are
  not applied to the call attempt. This allows for a remote attacker who is aware
  of a peer's credentials to bypass the ACL rules set for that peer.

  This patch ensures that the ACLs are applied for all peers, regardless of their
  storage mechanism.

  (closes issue ASTERISK-20186)
  Reported by: Alan Frisch
  Tested by: mjordan, Alan Frisch
  ........

  Merged revisions 372015 from http://svn.asterisk.org/svn/asterisk/branches/1.8
................

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/10-digiumphones@372027 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/README-SERIOUSLY.bestpractices.txt b/README-SERIOUSLY.bestpractices.txt
index 0e2af3b4a407635a5b515fedb3a6f52b43970eb4..b470fd66cf57f13aaa0fc559b8b407186d979e6f 100644 (file)
--- a/README-SERIOUSLY.bestpractices.txt
+++ b/README-SERIOUSLY.bestpractices.txt
@@ -23,6 +23,9 @@ Sections
 * Reducing Pattern Match Typos: 
         Using the 'same' prefix, or using Goto()
 
+* Manager Class Authorizations:
+        Recognizing potential issues with certain classes of authorization
+
 ----------------
 Additional Links
 ----------------
@@ -293,3 +296,51 @@ same => n,Hangup()
 exten => error,1,Verbose(2,Unable to lookup technology or device for extension)
 same => n,Playback(silence/1&num-not-in-db)
 same => n,Hangup()
+
+
+============================
+Manager Class Authorizations
+============================
+
+Manager accounts have associated class authorizations that define what actions
+and events that account can execute/receive.  In order to run Asterisk commands
+or dialplan applications that affect the system Asterisk executes on, the
+"system" class authorization should be set on the account.
+
+However, Manager commands that originate new calls into the Asterisk dialplan
+have the potential to alter or affect the system as well, even though the
+class authorization for origination commands is "originate".  Take, for example,
+the Originate manager command:
+
+Action: Originate
+Channel: SIP/foo
+Exten: s
+Context: default
+Priority: 1
+Application: System
+Data: echo hello world!
+
+This manager command will attempt to execute an Asterisk application, System,
+which is normally associated with the "system" class authorication.  While some
+checks have been put into Asterisk to take this into account, certain dialplan
+configurations and/or clever manipulation of the Originate manager action can
+circumvent these checks.  For example, take the following dialplan:
+
+exten => s,1,Verbose(Incoming call)
+same => n,MixMonitor(foo.wav,,${EXEC_COMMAND})
+same => n,Dial(SIP/bar)
+same => n,Hangup()
+
+Whatever has been defined in the variable EXEC_COMMAND will be executed after
+MixMonitor has finished recording the call.  The dialplan writer may have
+intended that this variable to be set by some other location in the dialplan;
+however, the Manager action Originate allows for channel variables to be set by
+the account initiating the new call.  This could allow the Originate action to
+execute some command on the system by setting the EXEC_COMMAND dialplan variable
+in the Variable: header.
+
+In general, you should treat the Manager class authorization "originate" the
+same as the class authorization "system".  Good system configuration, such as
+not running Asterisk as root, can prevent serious problems from arising when
+allowing external connections to originate calls into Asterisk.
+

diff --git a/channels/chan_iax2.c b/channels/chan_iax2.c
index 5793e961677cd498cb1b54c1b038d1f5b88ca78e..841eeb6c7fc753e238b38368355c873ed616a0b2 100644 (file)
--- a/channels/chan_iax2.c
+++ b/channels/chan_iax2.c
@@ -7720,10 +7720,10 @@ static int check_access(int callno, struct sockaddr_in *sin, struct iax_ies *ies
        i = ao2_iterator_init(users, 0);
        while ((user = ao2_iterator_next(&i))) {
                if ((ast_strlen_zero(iaxs[callno]->username) ||                         /* No username specified */
-                       !strcmp(iaxs[callno]->username, user->name))    /* Or this username specified */
-                       && ast_apply_ha(user->ha, &addr)        /* Access is permitted from this IP */
+                       !strcmp(iaxs[callno]->username, user->name))                    /* Or this username specified */
+                       && ast_apply_ha(user->ha, &addr) == AST_SENSE_ALLOW             /* Access is permitted from this IP */
                        && (ast_strlen_zero(iaxs[callno]->context) ||                   /* No context specified */
-                            apply_context(user->contexts, iaxs[callno]->context))) {                   /* Context is permitted */
+                               apply_context(user->contexts, iaxs[callno]->context))) {                        /* Context is permitted */
                        if (!ast_strlen_zero(iaxs[callno]->username)) {
                                /* Exact match, stop right now. */
                                if (best)
@@ -7779,8 +7779,9 @@ static int check_access(int callno, struct sockaddr_in *sin, struct iax_ies *ies
        user = best;
        if (!user && !ast_strlen_zero(iaxs[callno]->username)) {
                user = realtime_user(iaxs[callno]->username, sin);
-               if (user && !ast_strlen_zero(iaxs[callno]->context) &&                  /* No context specified */
-                   !apply_context(user->contexts, iaxs[callno]->context)) {            /* Context is permitted */
+               if (user && (ast_apply_ha(user->ha, &addr) == AST_SENSE_DENY            /* Access is denied from this IP */
+                       || (!ast_strlen_zero(iaxs[callno]->context) &&                                  /* No context specified */
+                               !apply_context(user->contexts, iaxs[callno]->context)))) {      /* Context is permitted */
                        user = user_unref(user);
                }
        }

diff --git a/main/manager.c b/main/manager.c
index 5f753587fe26a75618938292a830ed963906d631..4a50c0c72f9ac873bbb2d850ded0290da1b77647 100644 (file)
--- a/main/manager.c
+++ b/main/manager.c
@@ -4143,6 +4143,7 @@ static int action_originate(struct mansession *s, const struct message *m)
                                strcasestr(app, "agi") ||         /* AGI(/bin/rm,-rf /)
                                                                     EAGI(/bin/rm,-rf /)       */
                                strcasestr(app, "mixmonitor") ||  /* MixMonitor(blah,,rm -rf)  */
+                               strcasestr(app, "externalivr") || /* ExternalIVR(rm -rf)       */
                                (strstr(appdata, "SHELL") && (bad_appdata = 1)) ||       /* NoOp(${SHELL(rm -rf /)})  */
                                (strstr(appdata, "EVAL") && (bad_appdata = 1))           /* NoOp(${EVAL(${some_var_containing_SHELL})}) */
                                )) {