All versions of Samba starting with 4.21.0 are vulnerable to a improper authorization issue. smbd does not pick up group membership changes when re-authenticating an expired SMB session.
Nick Tait <ntait () redhat com> wrote: [1] Heap Buffer Overflow in Rsync due to Improper Checksum Length Handling
CVE ID: CVE-2024-12084
CVSS 3.1: 9.8 - AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Description: A heap-based buffer overflow flaw was found in the rsync daemon. This issue is due to improper handling of attacker-controlled checksum lengths (s2length) in the code. When MAXDIGESTLEN exceeds the fixed SUMLENGTH (16 bytes), an attacker can write out of bounds in the sum2 buffer. Does anybody know if this issue is also present in the code executing when you use SSH instead of rsyncd?
I'd expect the "rsync --server --sender" functionality to possibly (likely?) share code here, but the current description might lead folks to not consider this scenario and only look for cases where they offer rsyncd (e.g., port 873).
-Jan
Hi Douglas,
On Tue, Jun 25, 2024 at 11:49:40AM +1200, Douglas Bagnall wrote: So Samba was very susceptible to this bug. The good news is ldbqsort() is not used in very many places, and some of those places already used transitive comparison functions. The other good news is that now it is patched with the "tmpptr > baseptr &&" fix. And the third good news is that the comparison functions are fixed. That's in 4.19.7 and 4.20.2. This is really interesting, thank you very much for your work on all this and for taking the time to write this detailed analysis! We are extremely happy that our advisory has been useful.
With best regards,
-- the Qualys Security Advisory team
A heap-based Buffer Overflow flaw was discovered in Samba. It could allow a remote, authenticated attacker to exploit this vulnerability to cause a denial of service.
A vulnerability was discovered in Samba, where the flaw allows SMB clients to truncate files, even with read-only permissions when the Samba VFS module "aclxattr" is configured with "aclxattr:ignore system acls = yes". The SMB protocol allows opening files when the client requests read-only access but then implicitly truncates the opened file to 0 bytes if the client specifies a separate OVERWRITE create disposition request. The issue arises in configurations that bypass kernel file system permissions checks, relying solely on Samba's permissions.
A flaw was found in Samba. It is susceptible to a vulnerability where multiple incompatible RPC listeners can be initiated, causing disruptions in the AD DC service. When Samba's RPC server experiences a high load or unresponsiveness, servers intended for non-AD DC purposes (for example, NT4-emulation "classic DCs") can erroneously start and compete for the same unix domain sockets. This issue leads to partial query responses from the AD DC, causing issues such as "The procedure number is out of range" when using tools like Active Directory Users. This flaw allows an attacker to disrupt AD DC services.
A design flaw was found in Samba's DirSync control implementation, which exposes passwords and secrets in Active Directory to privileged users and Read-Only Domain Controllers (RODCs). This flaw allows RODCs and users possessing the GETCHANGES right to access all attributes, including sensitive secrets and passwords. Even in a default setup, RODC DC accounts, which should only replicate some passwords, can gain access to all domain secrets, including the vital krbtgt, effectively eliminating the RODC / DC distinction. Furthermore, the vulnerability fails to account for error conditions (fail open), like out-of-memory situations, potentially granting access to secret attributes, even under low-privileged attacker influence.
A vulnerability was found in Samba's "rpcecho" development server, a non-Windows RPC server used to test Samba's DCE/RPC stack elements. This vulnerability stems from an RPC function that can be blocked indefinitely. The issue arises because the "rpcecho" service operates with only one worker in the main RPC task, allowing calls to the "rpcecho" server to be blocked for a specified time, causing service disruptions. This disruption is triggered by a "sleep()" call in the "dcesrvechoTestSleep()" function under specific conditions. Authenticated users or attackers can exploit this vulnerability to make calls to the "rpcecho" server, requesting it to block for a specified duration, effectively disrupting most services and leading to a complete denial of service on the AD DC. The DoS affects all other services as "rpcecho" runs in the main RPC task.
A path traversal vulnerability was identified in Samba when processing client pipe names connecting to Unix domain sockets within a private directory. Samba typically uses this mechanism to connect SMB clients to remote procedure call (RPC) services like SAMR LSA or SPOOLSS, which Samba initiates on demand. However, due to inadequate sanitization of incoming client pipe names, allowing a client to send a pipe name containing Unix directory traversal characters (../). This could result in SMB clients connecting as root to Unix domain sockets outside the private directory. If an attacker or client managed to send a pipe name resolving to an external service using an existing Unix domain socket, it could potentially lead to unauthorized access to the service and consequential adverse events, including compromise or service crashes.
This vulnerability allows remote attackers to create a denial-of-service condition on affected installations of Samba. Authentication is not required to exploit this vulnerability.
This vulnerability allows remote attackers to create a denial-of-service condition on affected installations of Samba. Authentication is not required to exploit this vulnerability.
This vulnerability allows remote attackers to disclose sensitive information on affected installations of Samba. Authentication is not required to exploit this vulnerability.
This vulnerability allows remote attackers to disclose sensitive information on affected installations of Samba. Authentication is not required to exploit this vulnerability.
An out-of-bounds read vulnerability was found in Samba due to insufficient length checks in winbinddpamauthcrap.c. When performing NTLM authentication, the client replies to cryptographic challenges back to the server. These replies have variable lengths, and Winbind fails to check the lan manager response length. When Winbind is used for NTLM authentication, a maliciously crafted request can trigger an out-of-bounds read in Winbind, possibly resulting in a crash.
This vulnerability allows remote attackers to disclose sensitive information on affected installations of Samba. Authentication is required to exploit this vulnerability, and SMB1 must be enabled on the target.
This vulnerability allows remote attackers to disclose sensitive information on affected installations of Samba. Authentication is required to exploit this vulnerability, and SMB1 must be enabled on the target.
The Samba AD DC administration tool, when operating against a remote LDAP server, will by default send new or reset passwords over a signed-only connection.
A flaw was found in Samba. An incomplete access check on dnsHostName allows authenticated but otherwise unprivileged users to delete this attribute from any object in the directory.
The fix in 4.6.16, 4.7.9, 4.8.4 and 4.9.7 for CVE-2018-10919 Confidential attribute disclosure vi LDAP filters was insufficient and an attacker may be able to obtain confidential BitLocker recovery keys from a Samba AD DC.
Since the Windows Kerberos RC4-HMAC Elevation of Privilege Vulnerability was disclosed by Microsoft on Nov 8 2022 and per RFC8429 it is assumed that rc4-hmac is weak, Vulnerable Samba Active Directory DCs will issue rc4-hmac encrypted tickets despite the target server supporting better encryption (eg aes256-cts-hmac-sha1-96).
PAC parsing in MIT Kerberos 5 (aka krb5) before 1.19.4 and 1.20.x before 1.20.1 has integer overflows that may lead to remote code execution (in KDC, kadmind, or a GSS or Kerberos application server) on 32-bit platforms (which have a resultant heap-based buffer overflow), and cause a denial of service on other platforms. This occurs in krb5pacparse in lib/krb5/krb/pac.c. Heimdal before 7.7.1 has "a similar bug."
Heimdal before 7.7.1 allows remote attackers to execute arbitrary code because of an invalid free in the ASN.1 codec used by the Key Distribution Center (KDC).
DISPUTED A vulnerability classified as problematic has been found in ppp. Affected is the function dumpppp of the file pppdump/pppdump.c of the component pppdump. The manipulation of the argument spkt.buf/rpkt.buf leads to improper validation of array index. The real existence of this vulnerability is still doubted at the moment. The name of the patch is a75fb7b198eed50d769c80c36629f38346882cbf. It is recommended to apply a patch to fix this issue. VDB-216198 is the identifier assigned to this vulnerability. NOTE: pppdump is not used in normal process of setting up a PPP connection, is not installed setuid-root, and is not invoked automatically in any scenario.
A symlink following vulnerability was found in Samba, where a user can create a symbolic link that will make 'smbd' escape the configured share path. This flaw allows a remote user with access to the exported part of the file system under a share via SMB1 unix extensions or NFS to create symlinks to files outside the 'smbd' configured share path and gain access to another restricted server's filesystem.
A heap-based buffer overflow vulnerability was found in Samba within the GSSAPI unwrapdes() and unwrapdes3() routines of Heimdal. The DES and Triple-DES decryption routines in the Heimdal GSSAPI library allow a length-limited write buffer overflow on malloc() allocated memory when presented with a maliciously small packet. This flaw allows a remote user to send specially crafted malicious data to the application, possibly resulting in a denial of service (DoS) attack.
Samba does not validate the Validated-DNS-Host-Name right for the dNSHostName attribute which could permit unprivileged users to write it.
In Samba, GnuTLS gnutlsrnd() can fail and give predictable random values.
A flaw was found in Samba. Samba AD users can cause the server to access uninitialized data with an LDAP add or modify the request, usually resulting in a segmentation fault.
A flaw was found in the Samba AD LDAP server. The AD DC database audit logging module can access LDAP message values freed by a preceding database module, resulting in a use-after-free issue. This issue is only possible when modifying certain privileged attributes, such as userAccountControl.
A flaw was found in Samba. The KDC accepts kpasswd requests encrypted with any key known to it. By encrypting forged kpasswd requests with its own key, a user can change other users' passwords, enabling full domain takeover.