Totemo Email Encryption Gateway up to 6.0 JSONP Callback Key information disclosure

CVSS Meta Temp Score
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CTI Interest Score
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5.7$0-$5k0.00

Summaryinfo

A vulnerability was found in Totemo Email Encryption Gateway up to 6.0 and classified as problematic. Affected is an unknown function of the component JSONP Callback Handler. The manipulation results in information disclosure (Key). This vulnerability is identified as CVE-2018-6562. The attack can be executed remotely. Additionally, an exploit exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Totemo Email Encryption Gateway up to 6.0. It has been classified as problematic. Affected is an unknown code of the component JSONP Callback Handler. The manipulation with an unknown input leads to a information disclosure vulnerability (Key). CWE is classifying the issue as CWE-200. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. This is going to have an impact on confidentiality. CVE summarizes:

totemomail Encryption Gateway before 6.0_b567 allows remote attackers to obtain sensitive information about user sessions and encryption key material via a JSONP hijacking attack.

The bug was discovered 05/15/2018. The weakness was released 05/15/2018 by Nicolas Heiniger with CSNC as CSNC-2018-002 as confirmed posting (Bugtraq). The advisory is shared for download at securityfocus.com. The public release was coordinated with the vendor. This vulnerability is traded as CVE-2018-6562 since 02/02/2018. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Technical details are unknown but a public exploit is available. The MITRE ATT&CK project declares the attack technique as T1592. The advisory points out:

When sending an encrypted email to a recipient outside of the organization, totemomail Encryption Gateway sends a so-called Envelope Message that includes an HTML file with the encrypted content and JavaScript to get the key from the gateway to decrypt the content. The key material is provided by the gateway through a JSONP callback that must be either authenticated using the email and password in the POST request or with an existing session ID.

A public exploit has been developed by Nicolas Heiniger in HTTP GET Request and been published immediately after the advisory. The exploit is shared for download at securityfocus.com. It is declared as proof-of-concept. The vulnerability was handled as a non-public zero-day exploit for at least 51 days. During that time the estimated underground price was around $5k-$25k. The code used by the exploit is:

GET /responsiveUI/EnvelopeOpenServlet?envelopeAction=decryptionKey&messageId=160_1&callback=jsonpCallback&usermail=[CUT BY COMPASS]&password=[CUT BY COMPASS]&usermtan=&_=1515597892513 HTTP/1.1
Host: [CUT BY COMPASS]
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Firefox/52.0
Accept: */*
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Cookie: JSESSIONID=EF8E33D6DAD75F0394381AB7084DEA2D;oam.Flash.RENDERMAP.TOKEN=uy9dqvc4a
Connection: close
The advisory illustrates:
The problem arises because the same request is accepted if a session already exists on the Encryption Gateway. In this case, the username and password are not required. This enables an attacker to create a malicious web page that will define a JavaScript function 'jsonpCallback' and insert a script tag with the source on the Encryption Gateway. This way, it is possible to retrieve the response in the callback if a logged in user visits the malicious page.

Upgrading to version 6.0_b567 eliminates this vulnerability. A possible mitigation has been published before and not just after the disclosure of the vulnerability. The posting contains the following remark:

As a developer, JSONP callbacks should not include sensitive information. If they need to, the request must include an unpredictable element. In this case a possibility would be to require the email and the password of the user even if the session is open.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.1

VulDB Base Score: 5.3
VulDB Temp Score: 4.8
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Name: Key
Class: Information disclosure / Key
CWE: CWE-200 / CWE-284 / CWE-266
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Proof-of-Concept
Author: Nicolas Heiniger
Programming Language: 🔍
Download: 🔍

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exploit Delay Time: 🔍

Upgrade: Email Encryption Gateway 6.0_b567

Timelineinfo

02/02/2018 🔍
02/09/2018 +7 days 🔍
03/13/2018 +32 days 🔍
04/01/2018 +19 days 🔍
05/15/2018 +44 days 🔍
05/15/2018 +0 days 🔍
05/15/2018 +0 days 🔍
05/18/2018 +2 days 🔍
05/19/2018 +1 days 🔍
02/07/2020 +629 days 🔍

Sourcesinfo

Advisory: CSNC-2018-002⛔
Researcher: Nicolas Heiniger
Organization: CSNC
Status: Confirmed
Coordinated: 🔍

CVE: CVE-2018-6562 (🔍)
GCVE (CVE): GCVE-0-2018-6562
GCVE (VulDB): GCVE-100-117996
scip Labs: https://www.scip.ch/en/?labs.20161013

Entryinfo

Created: 05/19/2018 09:13
Updated: 02/07/2020 13:31
Changes: 05/19/2018 09:13 (80), 02/07/2020 13:31 (1)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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