Vulnerabilities > CVE-2017-2864 - Improper Authentication vulnerability in Meetcircle Circle With Disney Firmware 2.0.1
Attack vector
NETWORK Attack complexity
LOW Privileges required
NONE Confidentiality impact
HIGH Integrity impact
HIGH Availability impact
HIGH Summary
An exploitable vulnerability exists in the generation of authentication token functionality of Circle with Disney. Specially crafted network packets can cause a valid authentication token to be returned to the attacker resulting in authentication bypass. An attacker can send a series of packets to trigger this vulnerability.
Vulnerable Configurations
Part | Description | Count |
---|---|---|
OS | 1 | |
Hardware | 1 |
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Authentication Abuse An attacker obtains unauthorized access to an application, service or device either through knowledge of the inherent weaknesses of an authentication mechanism, or by exploiting a flaw in the authentication scheme's implementation. In such an attack an authentication mechanism is functioning but a carefully controlled sequence of events causes the mechanism to grant access to the attacker. This attack may exploit assumptions made by the target's authentication procedures, such as assumptions regarding trust relationships or assumptions regarding the generation of secret values. This attack differs from Authentication Bypass attacks in that Authentication Abuse allows the attacker to be certified as a valid user through illegitimate means, while Authentication Bypass allows the user to access protected material without ever being certified as an authenticated user. This attack does not rely on prior sessions established by successfully authenticating users, as relied upon for the "Exploitation of Session Variables, Resource IDs and other Trusted Credentials" attack patterns.
- Exploiting Trust in Client (aka Make the Client Invisible) An attack of this type exploits a programs' vulnerabilities in client/server communication channel authentication and data integrity. It leverages the implicit trust a server places in the client, or more importantly, that which the server believes is the client. An attacker executes this type of attack by placing themselves in the communication channel between client and server such that communication directly to the server is possible where the server believes it is communicating only with a valid client. There are numerous variations of this type of attack.
- Utilizing REST's Trust in the System Resource to Register Man in the Middle This attack utilizes a REST(REpresentational State Transfer)-style applications' trust in the system resources and environment to place man in the middle once SSL is terminated. Rest applications premise is that they leverage existing infrastructure to deliver web services functionality. An example of this is a Rest application that uses HTTP Get methods and receives a HTTP response with an XML document. These Rest style web services are deployed on existing infrastructure such as Apache and IIS web servers with no SOAP stack required. Unfortunately from a security standpoint, there frequently is no interoperable identity security mechanism deployed, so Rest developers often fall back to SSL to deliver security. In large data centers, SSL is typically terminated at the edge of the network - at the firewall, load balancer, or router. Once the SSL is terminated the HTTP request is in the clear (unless developers have hashed or encrypted the values, but this is rare). The attacker can utilize a sniffer such as Wireshark to snapshot the credentials, such as username and password that are passed in the clear once SSL is terminated. Once the attacker gathers these credentials, they can submit requests to the web service provider just as authorized user do. There is not typically an authentication on the client side, beyond what is passed in the request itself so once this is compromised, then this is generally sufficient to compromise the service's authentication scheme.
- Man in the Middle Attack This type of attack targets the communication between two components (typically client and server). The attacker places himself in the communication channel between the two components. Whenever one component attempts to communicate with the other (data flow, authentication challenges, etc.), the data first goes to the attacker, who has the opportunity to observe or alter it, and it is then passed on to the other component as if it was never intercepted. This interposition is transparent leaving the two compromised components unaware of the potential corruption or leakage of their communications. The potential for Man-in-the-Middle attacks yields an implicit lack of trust in communication or identify between two components.
Seebug
bulletinFamily exploit description ### Summary An exploitable vulnerability exists in the /api/CONFIG/backup functionality of Circle with Disney. Specially crafted network packets can cause an OS command injection. An attacker can send an HTTP request trigger this vulnerability. ### Tested Versions Circle with Disney ### Product URLs https://meetcircle.com/ ### CVSSv3 Score 9.9 - CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H ### CWE CWE-77: Improper Neutralization of Special Elements used in a Command ('Command Injection') ### Details Vulnerable code exists in the backup api handler of the apid deamon ("/api/CONFIG/backup"). ``` vulnerable code listing .text:00415E10 loc_415E10: .text:00415E10 lui $s0, 0x43 .text:00415E14 jal unlink .text:00415E18 addiu $a0, $s0, (aMntSharesUs_15 - 0x430000) # "/mnt/shares/usr/bin/backup.bin" .text:00415E1C la $s0, aMntSharesUs_15 # "/mnt/shares/usr/bin/backup.bin" .text:00415E20 lui $a2, 0x43 .text:00415E24 lui $a3, 0x43 .text:00415E28 li $a1, 0x80 # maxlen .text:00415E2C la $a2, aScreate_backup # "%screate_backup.sh %s %s" .text:00415E30 la $a3, aMntSharesUs_16 # "/mnt/shares/usr/bin/scripts/" .text:00415E34 addiu $a0, $sp, 0x21B0+var_F8 # s .text:00415E38 sw $s0, 0x21B0+var_21A0($sp) .text:00415E3C jal snprintf .text:00415E40 sw $s2, 0x21B0+var_219C($sp) .text:00415E44 jal system ``` Looking at the pseudocode of the above, we see the following: ``` Line 1 if (strncmp((char *)request_url, "/api/CONFIG/", 12) == 0) { Line 2 if (strcmp((char *)(request_url + 12), "backup") == 0) { Line 3 appid_value = get_param_from_url("appid", 1); Line 4 if (appid_value != 0 && strlen((char *)appid_value) >= 20) { Line 5 unlink("/mnt/shares/usr/bin/backup.bin"); Line 6 snprintf((char *)&cmd, 128, "%screate_backup.sh %s %s", "/mnt/shares/usr/bin/scripts/", "/mnt/shares/usr/bin/backup.bin", (char *)appid_value); Line 7 system((char *)&cmd); ``` As we can see `appid` parameter coming from user as GET parameter is passed direcly to `system` call without any sanitization leading in that way to command injection. This API is accessible for authenticated users. But taking into account the weak authentication vulnerability (TALOS-2017-0370/CVE-2017-2864) anyone can use this API. An example of a url that contains the command injection can look like this: ``` https://CIRCLE_IP:4567/api/CONFIG/backup?token=8CE2DAF0F3C9-iNvDFypBs0RXv2jy- 20170621.085252&api=1.0&appid=AAAAAAAAAAAAAAAAAAAA;ls>/tmp/file_listing.txt Notes: For proper commands/params separation, a malicious user needs to use tabs instead of spaces. ``` ### Timeline * 2017-07-13 - Vendor Disclosure * 2017-10-31 - Public Release ### CREDIT Discovered by Marcin 'Icewall' Noga, Cory Duplantis, Yves Younan, Claudio Bozzato, Lilith Wyatt <(^_^)>, Aleksandar Nikolic, and Richard Johnson Cisco Talos. id SSV:96819 last seen 2017-11-19 modified 2017-11-08 published 2017-11-08 reporter Root title Circle with Disney Backup API Command Injection Vulnerability(CVE-2017-2866) bulletinFamily exploit description ### Summary An exploitable vulnerability exists in the generation of authentication token functionality of Circle with Disney. Specially crafted network packets can cause a valid authentication token to be returned to the attacker resulting in authentication bypass. An attacker can send a series of packets to trigger this vulnerability. ### Tested Versions Circle with Disney ### Product URLs https://meetcircle.com/ ### CVSSv3 Score 9.8 - CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H ### CWE CWE-639 - Authorization Bypass Through User-Controlled Key ### Details Circle with Disney is a network device used to monitor internet use of children on a given network. When making any requests to the Circle, an authenticated token must be provided. To request a token, a client specifies an `appid`, a unique string used to identify the client, as well as a `hash`, a `SHA1` hash to verify the client should have access to the device. One secret piece of information is a 4 digit pin. The `hash` is calculated by the following: ``` hash = SHA1(appid + pin) ``` The client provides both the `appid` and `hash`. Because the key space for the `pin` is only `10000`, an attacker can easily brute force this pin to retrieve an authentication token. With the authentication token in hand, an attacker can make available API calls. ### Timeline * 2017-07-13 - Vendor Disclosure * 2017-10-31 - Public Release ### CREDIT Discovered by Cory Duplantis, Yves Younan, Marcin 'Icewall' Noga, Claudio Bozzato, Lilith Wyatt <(^_^)>, Aleksandar Nikolic, and Richard Johnson of Cisco Talos. id SSV:96817 last seen 2017-11-19 modified 2017-11-08 published 2017-11-08 reporter Root title Circle with Disney Weak Authentication Vulnerability(CVE-2017-2864)
Talos
id TALOS-2017-0372 last seen 2019-05-29 published 2017-10-31 reporter Talos Intelligence source http://www.talosintelligence.com/vulnerability_reports/TALOS-2017-0372 title Circle with Disney Backup API Command Injection Vulnerability id TALOS-2017-0370 last seen 2019-05-29 published 2017-10-31 reporter Talos Intelligence source http://www.talosintelligence.com/vulnerability_reports/TALOS-2017-0370 title Circle with Disney Weak Authentication Vulnerability