-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 Advisory ID: SYSS-2015-001 Product: Kaspersky Endpoint Security for Windows (KES) Manufacturer: Kaspersky Lab ZAO Affected Version(s): 8.1.0.1042, 10.2.1.23 Tested Version(s): 8.1.0.1042, 10.2.1.23 Vulnerability Type: Authentication Bypass Using an Alternate Path or Channel (CWE-288) Risk Level: Medium Solution Status: Fixed Vendor Notification: 2015-02-19 Solution Date: 2015-10-01 Public Disclosure: 2015-10-01 CVE Reference: Not yet assigned Authors of Advisory: Sven Freund and Matthias Deeg (SySS GmbH) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Overview: Kaspersky Endpoint Security for Windows provides centralized protection of Windows workstations and Windows servers from malware, potentially dangerous programs and network attacks. It includes features such as data encryption functionality for encrypting hard drives and removable devices, centralized vulnerability flagging and virtual machine support (see [1]). ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Vulnerability Details: The Kaspersky Endpoint Security for Windows software allows users to disable the offered protection by entering a so-called unload password. Beside the graphical user interface (GUI) authentication, it is also possible to manually deactivate the protection over the command-line interface using the Kaspersky software tool avp.exe. By analyzing the password-based authentication for unloading the Kaspersky Endpoint Security for Windows protection, the SySS GmbH found out, that the password comparison is done within the process avp.exe, which runs or can be run in the context of the current Windows user, who can also be a standard, limited user. This fact allows a further analysis and the manipulation of the password comparison during runtime without administrative privileges, as every user is able to debug and manipulate the processes running with her user privileges. In order to bypass the password-based authentication to deactivate the protection of Kaspersky Endpoint Security for Windows in an unauthorized manner, an attacker only has to patch this password comparison, so that it always returns true, for example by comparing the correct unload password with itself or by modifying the program control flow. The SySS GmbH also found out, that by modifying the software tool avp.exe, the Kaspersky Endpoint Security for Windows can also be deactivated completely even when no password was set for protecting administrative functions. The intended behavior of the software tool avp.exe in this case is to deny access to the requested function, for example "exit", due to a disabled password protection. Thus, a limited Windows user or malware running in the context of such a user is able to unload Kaspersky Endpoint Security for Windows in an unauthorized manner regardless of the configured password protection. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Proof of Concept (PoC): The SySS GmbH developed a proof-of-concept software tool named UnloadKES for deactivating Kaspersky Endpoint Security for Windows in an unauthorized manner. The following output exemplarily shows a successful deactivation of Kaspersky Endpoint Security for Windows: >UnloadKES.exe ____________________________________________________________ / _____ _____ _____ \ / / ___| / ___/ ___| \ | \ `--. _ _\ `--.\ `--. | | `--. \ | | |`--. \`--. \ | | /\__/ / |_| /\__/ /\__/ / | \ \____/ \__, \____/\____/ ... unloads KES! / \ __/ | / / |___/ _________________________________________/ / _________________/ (__) /_/ (oo) /------\/ / |____|| * || || ^^ ^^ SySS Unload KES v1.0 by Sven Freund & Matthias Deeg - SySS GmbH (c) 2015 [+] Found location of the executable file avp.exe [+] Created new instance of the Kaspersky Endpoint Security process avp.exe [+] The Kaspersky Endpoint Security process was patched successfully. Kaspersky Endpoint Security will now exit without a password. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Solution: According to information by Kaspersky, the described security issue has been fixed in newer software releases. Please contact the manufacturer for further information or support. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Disclosure Timeline: 2015-02-19: Vulnerability reported to manufacturer 2015-02-19: Manufacturer acknowledges e-mail with SySS security advisory 2015-03-17: Rescheduling of the publication date in agreement with the manufacturer 2015-04-14: Rescheduling of the publication date in agreement with the manufacturer 2015-05-21: Manufacturer asks for PoC software tool 2015-05-22: SySS sent PoC software tool to manufacturer 2015-09-28: SySS asks for further information about software fix 2015-10-01: Public release of security advisory on agreed publication date ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ References: [1] Product Web site for Kaspersky Endpoint Security for Windows http://support.kaspersky.com/kes10wks [2] SySS Security Advisory SYSS-2015-001 https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2015-001.txt [3] SySS Responsible Disclosure Policy https://www.syss.de/en/news/responsible-disclosure-policy/ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Credits: This security vulnerability was found by Sven Freund and Matthias Deeg of the SySS GmbH. E-Mail: sven.freund (at) syss.de Public Key: https://www.syss.de/fileadmin/dokumente/Materialien/PGPKeys/Sven_Freund.asc Key fingerprint = DCDB 7627 C1E3 9CE8 62DF 2666 8A5F A853 415D 46DC E-Mail: matthias.deeg (at) syss.de Public Key: https://www.syss.de/fileadmin/dokumente/Materialien/PGPKeys/Matthias_Deeg.asc Key fingerprint = D1F0 A035 F06C E675 CDB9 0514 D9A4 BF6A 34AD 4DAB ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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 Web site. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Copyright: Creative Commons - Attribution (by) - Version 3.0 URL: http://creativecommons.org/licenses/by/3.0/deed.en -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBCgAGBQJWDPBXAAoJENmkv2o0rU2rPRcQAIHaDvlvUPaSFnpdZeEwDiiz jizF+DT0Z8XA4Dve/xA59bXE9zM0wEQeUHrNfH7yeRg/SIxTyE0YwtQlf/St/ks9 oDkuLF/vue47vKx265Qdlx/7w0C98JxP9k+wyFZ/txj79pBOsRMeEKxRx1W6Km63 qUyYve3uaJu57ZAIEU5+TvvvWF2VuKNO79VOcKU3FPHiR31c2BgYrKFrVla6JbgF ND4wWLTmUS6SJCz3fMGjsFrVrPtQerY1pR4RAxOSXEOaAGIdYZBDoOr+bCvu2al7 quGQHCU55rn1OsGSSmjkg4hCGCo8Vurv4dR1U1f9kAtSXeWdx04Jw/KmjsvuD7B/ eFK6Br/V7dnH/mGFG9NWV8GA64YCNIiTvZB4b/u7TwDVAEHFVEf61hpneGgGnw2V SKzfFDAMUEnAXDWXvekDofux7EowYDXeAAPllBFD79Ey+SHh+n6qvJyaiwv9iuTR fFSAHOLGTeQweI4h5gtfOgh2+7Orvt3/0hJ1Tw8tuYG4ExtqbAEXcqSF3ga4hyI5 RM4j/rtOwXALdxntbnONKWwgB62Jmf9i13BnWRd1tknT+TiZwz6vdIbTvenA73fW RlCgVrWhi8JEPcbhkY3SZzmuIAH6+GTjz1Z4M7fe4jk2HafSHHuUlKtL14Z9xarT lEMgnegZmzud/7k+gmdl =MmMj -----END PGP SIGNATURE-----