-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 Advisory ID: SYSS-2024-017 Product: Ewon Cosy+ Manufacturer: HMS Industrial Networks AB Affected Version(s): Firmware Versions: < 21.2s10 and < 22.1s3 Tested Version(s): Firmware Version: 21.2s7 Vulnerability Type: Cleartext Storage of Sensitive Information in a Cookie (CWE-315) Risk Level: Low Solution Status: Fixed Manufacturer Notification: 2024-03-27 Solution Date: 2024-07-18 Public Disclosure: 2024-08-11 CVE Reference: CVE-2024-33892 Author of Advisory: Moritz Abrell, SySS GmbH ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Overview: The Ewon Cosy+ is a VPN gateway used for remote access and maintenance in industrial environments. The manufacturer describes the product as follows (see [1]): "The Ewon Cosy+ gateway establishes a secure VPN connection between the machine (PLC, HMI, or other devices) and the remote engineer. The connection happens through Talk2m, a highly secured industrial cloud service. The Ewon Cosy+ makes industrial remote access easy and secure like never before!" Due to cleartext storage of the password in a cookie, an attacker with appropriate access is able to retrieve the plaintext administrative password. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Vulnerability Details: The credentials used for the basic authentication against the web interface of Cosy+ are stored in the cookie "credentials" after a successful login. An attacker with access to a victim's browser is able to retrieve the administrative password of Cosy+. In addition, the cookie is not secured (no HttpOnly, Secure or SameSite attribute is set). Thus, the credentials could also be extracted in combination with cross-site scripting (XSS) vulnerabilities. Note: During the responsible disclosure process, SySS GmbH became aware of CVE-2015-7928[8], which describes an issue with password autocomplete in Ewon devices. Since this function contains the problematic cookie, this CVE may already describe the insecure cookie. SySS GmbH would therefore like to credit the reporter of CVE-2015-7928, Karn Ganeshen. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Proof of Concept (PoC): 1. "credentials" cookie value: YWRtOlN1cDNyUzNjcjN0IyM= 2. Decoded credentials: #> echo -n "YWRtOlN1cDNyUzNjcjN0IyM=" | base64 -d adm:Sup3rS3cr3t## Bonus: accessing the cookie from JavaScript code: <script>alert("Credentials can be access via JavaScript" + document.cookie)</script> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Solution: According to the manufacturer note[4], the vulnerability was fixed with the firmware versions 21.2s10 and 22.1s3. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Disclosure Timeline: 2024-03-26: Vulnerability discovered 2024-03-27: Vulnerability reported to manufacturer 2024-04-02: Inquiry about the status 2024-04-05: Manufacturer acknowlegded the vulnerability and started the analysis 2024-04-10: Two more vulnerabilities reported to the manufacturer (SYSS-2024-032 and SYSS-2024-033) 2024-04-11: Manufacturer acknowlegded the vulnerabilities and asked for a publication date for all findings 2024-04-12: Proposed dates for a discussion about publication 2024-04-15: Manufacturer sent a technical overview of planned remediation actions and details about the planned timeline 2024-04-15: Acknowlegded the remediation actions and asked the manufacturer to assign a CVE ID 2024-04-30: CVE ID CVE-2024-33893[5] assigned by the manufacturer 2024-05-31: Manufacturer informed that the fix is in completion stage and asked if the blog post[6] can be reviewed by HMS 2024-06-04: Proposed dates to review the blog post draft 2024-06-21: Inquiry about the status 2024-06-21: Received an out-of-office auto reply 2024-07-01: Inquiry about the status 2024-07-04: Inquiry about the status 2024-07-12: Inquiry about the status and letting the manufacturer know that the vulnerability will be published within a talk at DEF CON[7] in August 2024-07-12: Manufacturer responded that the fix is planned by the end of July; manufacturer asked again for reviewing the blog post draft 2024-07-12: Again confirmed reviewing the blog post is possible and asking for the sending of details 2024-07-17: Blog post provided to HMS 2024-07-18: Fixed firmware versions 21.2s10 and 22.1s3 released by HMS 2024-07-23: Inquiry about the status 2024-07-23: Manufacturer reviewed the blog post and confirmed that a fix is provided 2024-07-29: Discussion with HMS about the blog post and final publication actions 2024-08-11: Vulnerability disclosed at DEF CON[7] 2024-08-11: Blog post published[6] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ References: [1] Ewon Cosy+ product website https://www.hms-networks.com/p/ec71330-00ma-ewon-cosy-ethernet [2] SySS Security Advisory SYSS-2024-017 https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2024-017.txt [3] SySS Responsible Disclosure Policy https://www.syss.de/en/responsible-disclosure-policy [4] Manufacturer note https://hmsnetworks.blob.core.windows.net/nlw/docs/default-source/products/cybersecurity/security-advisory/hms-security-advisory-2024-07-29-001--ewon-several-cosy--vulnerabilities.pdf [5] CVE-2024-33892 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-33892 [6] Blog post https://blog.syss.com/posts/hacking-a-secure-industrial-remote-access-gateway/ [7] DEF CON talk https://defcon.org/html/defcon-32/dc-32-speakers.html#54521 [8] CVE-2015-7928 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-7928 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Credits: This security vulnerability was found by Moritz Abrell of SySS GmbH. E-Mail:moritz.abrell () syss de Public Key:https://www.syss.de/fileadmin/dokumente/PGPKeys/Moritz_Abrell.asc Key Fingerprint: 2927 7EB6 1A20 0679 79E9 87E6 AE0C 9BF8 F134 8B53 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Disclaimer: The information provided in this security advisory is provided "as is" and without warranty of any kind. Details of this security advisory may be updated in order to provide as accurate information as possible. The latest version of this security advisory is available on the SySS website. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Copyright: Creative Commons - Attribution (by) - Version 3.0 URL:http://creativecommons.org/licenses/by/3.0/deed.en -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEEKSd+thogBnl56Yfmrgyb+PE0i1MFAmay4zQACgkQrgyb+PE0 i1Oq5hAApN8Ekc20CgEg5KyIFK18sKBPzSA/SeZcSdUOkv8N05riytWxbVFuLBpS LhHH9spxUjn6Sr36JDp5dISCj9rtajrNE/adIiNC9LUhBRIr2h1ogFfh5zKK8N9D m4CXknQ3b2QQctkuhywyKSKjvNnvxj+k6nDIFlTzXdl3e9cEpisaAFr8zt9/jb7d ZBt8HHrEvJRCa5eBK40r0t42xFiWILh98enmLVCM2VOUnaAxz6JXLTunRSXqC6WH SzEOR/G32z+NxNCphPuswlIqfnhoaOFQ7oP2miuGglDdm5yWQX6E+xtp5HUelmkS DyZ6nUPOmr67lOgOUIhtIQp4zRYNiQAvDv70x9k/RCv+VDG4B5qEffFIbq6JgSCW Q+5iQXfDEJwuj0ePIe/wO+svn7C7LOSfvRfjw39GF0gTeKhPi8cNj5S+Jpl3M6pP XWEHcHzhVze9t5CLFgkh4GtmqH4OvWvFxn8d3x5h21eljloobUNZXAWlUYJdb6Ae gNhWD3IKQJyPo/4cyDC5iZS6QtivjyiQUb6aU6vqKWcR7tlnr7jferG00Q3Sz8R2 ddC8Vw78j2GvzyCibNhSoKGfjQAOhYgfsH8ktRDQ/zDYguT4cHA++V16MbfXwIv0 y3mQqModAAlpqYGVf4783H24kuyP19KewZuj5dSsMTyShIcTkCU= =LXSO -----END PGP SIGNATURE-----
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