-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 Advisory ID: SYSS-2022-042 Product: Printanista Hub (formerly Printscout) Manufacturer: ECi Software Solutions LTD (formerly FMAudit LLC) Affected Version(s): unknown Vulnerability Type: Asymmetric Resource Consumption (CWE-405) Risk Level: Medium Solution Status: Not fixed Manufacturer Notification: 2022-06-27 Solution Date: Not fixed Public Disclosure: 2022-09-15 CVE Reference: CVE-2022-40306 Author of Advisory: Thibaud Kehler, SySS GmbH ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Overview: Printanista Hub (former FMAudit Printscout) is a printing management web application. The manufacturer describes the product as follows (see [1]): "Printanista provides powerful functionality that reduces the complexity of supporting your customers’ diverse print environments." Due to an expensive key generation operation in the login form, the web application is susceptible to a denial-of-service attack that has been actively exploited. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Vulnerability Details: Every time the web server renders the login form, it generates a new RSA private/public key pair, as can be seen in the following HTTP request: ''' $ curl 'https:///Login' | nl [...] 168 function encryptPassword() { 169 var clearPass = $("#login-password").val(); 170 $("#login-passhash").val(null); 171 172 var publicKeyExponent = Base64.decode("AQAB"); 173 if (publicKeyExponent != false) { 174 175 var publicKeyModulus = Base64.decode("pHxCpuRqiDJigigqS3cm0Kvh+n+O40X8FSUSxANORGRlapedKdWJqnoKKx2sB/QR5kyxPBkiDcpsa1rVUn8PK4hcyU/psclJDiNk7zEmA4FhaiSwxf1vLGSstelFzlZSM0YmCx619dSpAxNB9fyRkp0R1WbPoGSLpdda9QibyDc="); 176 var publicKey = new RSAPublicKey(publicKeyModulus, publicKeyExponent); 177 var encryptedPass = RSA.encrypt(clearPass, publicKey); 178 179 $("#login-passhash").val(encryptedPass); 180 $("#login-password").val(null); 181 } 182 } [...] ''' The RSA key is used to encrypt the password in addition to any Transport Layer Security (TLS). Since no validation of the public key is conducted, the encryption by design is prone to machine-in-the- middle attacks and mostly useless in times where TLS is prevailing. Generating the necessary prime numbers, however, is an expensive cryptographic operation. Furthermore, the private key has to be stored on the server in order to decrypt incoming logins. An attacker can abuse the asymmetric resource consumption by sending multiple comparatively simple HTTP request in order to consume the web server's resources, potentially resulting in a denial of service. SySS has knowledge of an active denial-of-service attack relying on this vulnerability. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Solution: The vendor has not published any solution yet. As a mitigation, SySS recommends removing the additional RSA encryption completely in favor of a well-configured Transport Layer Security. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Disclosure Timeline: 2020-07-13: Vulnerability discovered 2022-06-27: Vulnerability reported to manufacturer 2022-09-09: CVE-2022-40306 assigned 2022-09-15: Public disclosure of vulnerability ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ References: [1] Product website for Printanista Hub https://www.ecisolutions.com/en-gb/products/printanista-hub/ [2] SySS Security Advisory SYSS-2022-042 https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2022-042.txt (not yet published) [3] SySS Responsible Disclosure Policy https://www.syss.de/en/responsible-disclosure-policy ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Credits: This security vulnerability was found by Thibaud Kehler of SySS GmbH. E-Mail: thibaud.kehler@syss.de Public Key: https://www.syss.de/fileadmin/dokumente/PGPKeys/Thibaud_Kehler.asc Key ID: 0xB6457D7A Key Fingerprint: CF29 54F1 1B7F 2FF5 7ED9 9BAD E9C7 9866 B645 7D7A ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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----- iQIzBAEBCgAdFiEEzylU8Rt/L/V+2Zut6ceYZrZFfXoFAmM/BGkACgkQ6ceYZrZF fXoU/BAAkU5IPMli6N6JIUwQgvC3ExJmtftC7hUUIce8c5zacUNXUoupXpvQRlYp k8Gw2kTeeBXDo9+W18Yo2atdMCAxvglGMMQB4d7a9usM25CQLhVDUBBW9JtgjyB+ Q26O3kNP04Q3gq0NzOPoUrTk00f757OOwwuFcVkWQOKqOvZtob/+KfTSLYwbzcu3 n96L4PTdoc5z/oK4qnQ9CZm0Jr2k+Ds47blTCjE9+KZ7aNK4r3DRhBYZpqkRzj2H SpALcWdGvSUdFvpw++KDXkv7p97Fz67FwMKDW3aWruCRxQQj+pgO4nBvsc3FXHoR juRgXPjOGe2/HsQPipV+MTX/l6ZKPT6fvq/jrEwH+SapMxZrkSyadcVVdzY6oN7J F2JokHXF487ogrShOtso2/hzLJwmehQ4OZ/83Y7P3BIRLaFbpfxA9rNkUAcrPtC6 LNGd2Ivykl6zoHNJvwT76O9wjXEalFIWihviON6NB0bsZD8n1+DByWM8vY51AgfG kaxjYob7O77TF/ieNqNyNYMp3EQF++h9nRDO41z3Sx768ESgR92xIWB7oWf0vTNt TnwH7s3ybHkxlqAxnslw/VIbQTtB9oarh9EpI5DPTx5rIkPbf7Ss6t4EWaaXqrsL mn02C0Kz9kxFRuFlUGmDlHSkrZgZWbafrFZ5qyMUojoA0V6jHCY= =arwx -----END PGP SIGNATURE-----