The NetApp ONTAP, however, still uses RC4. The good news is that this cipher is not used by most modern servers, such as Windows 7 and later. In the patch released for this vulnerability, the configurations by default have been set to: reject md5 clients = yes reject md5 servers = yes To combat this, the cipher must be disabled in Samba. If an attacker knows the plain text, they could create different data of their choice using the same MD5 checksum and substitute it in the data stream. The issue lies in the secure checksum that is calculated as HMAC-MD5(MD5(DATA)(KEY). Similarly, the RC4 mode in the NETLOGON Secure Channel is also vulnerable as they are the same ciphers. Kerberos uses weak RC4-HMAC cryptography. All features described in this article are available in the trial.CVE-2022-38023, with an 8.1 CVSS score, is a vulnerability associated with the RC4/HMAC-MD5 NetLogon Secure Channel. To start detecting and protecting against critical vulnerabilities, get a Qualys Suite trial. Note this can disable some expected functionality for Windows clients.” As with any workarounds, this should be fully tested in your environment before a large-scale deployment is performed. Please note that the Samba Team has also advised: “This prevents clients from accessing any named pipe endpoints. To the section of your smb.conf and restart smbd. WorkaroundsĪccording to the Samba security bulletin, there is a workaround available. The other vendor-specific QIDs require authentication and will identify the vendor-specific patch needed for remediation. QID 38671 offers remote (unauthenticated) detection of the vulnerability by identifying the underlying samba version. Qualys has provided several QIDs for detecting this vulnerability using Qualys Vulnerability Management, and will continue to add details as vendors release additional patches.ģ8671 Samba Writable Share Remote Code Execution Vulnerabilityġ70002 SUSE Enterprise Linux Security Update for samba (SUSE-SU-2017:1391-1)ġ70003 SUSE Enterprise Linux Security Update for samba (SUSE-SU-2017:1392-1)ġ70004 SUSE Enterprise Linux Security Update for samba (SUSE-SU-2017:1393-1)ġ96791 Ubuntu Security Notification for Samba Vulnerability (USN-3296-1)Ģ36359 Red Hat Update for samba (RHSA-2017-1270)Ģ36360 Red Hat Update for samba4 (RHSA-2017-1271)Ģ36361 Red Hat Update for samba3x (RHSA-2017-1272)ġ57455 Oracle Enterprise Linux Security Update for samba (ELSA-2017-1270)ġ57456 Oracle Enterprise Linux Security Update for samba4 (ELSA-2017-1271)ġ76040 Debian Security Update for samba (DSA 3860-1) Still, examples like this Samba vulnerability only continue to reinforce the ongoing need for continuous security visibility to prioritize patching and system configuration updates and for full data backups of critical files to ensure business resiliency. However, this vulnerability remains much more difficult to exploit, because it requires not only outdated software but also a specific configuration, such as anonymous write access to a share. malware can leverage it to spread automatically from system to system. It also carries the threat of being “wormable,” i.e. Similar to the vulnerability exploited by WannaCry, this exploit targets SMB, albeit a different implementation of the protocol. Questions have been raised on whether this vulnerability could pose the same risk as WannaCry, and this vulnerability does bear some similarities, but there are some key differences. The Samba Team may also release patches for older versions of Samba. While the Samba Team is providing patches for the latest versions (4.4.x and higher), some Linux vendors, such as RedHat and Ubuntu, are providing patches for older versions of Samba if they are used in a supported version of the OS. Samba is used to provide SMB and CIFS services for Linux systems, and is pervasive in both enterprise and consumer products. Exploitation of this vulnerability could result in remote code execution on the affected host. On Wednesday, the Samba Team patched a vulnerability that exists in all versions of Samba including and after version 3.5.0.
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