Vulnerabilities (CVE)

An elevation of privilege vulnerability exists when an attacker establishes a vulnerable Netlogon secure channel connection to a domain controller, using the Netlogon Remote Protocol (MS-NRPC). An attacker who successfully exploited the vulnerability could run a specially crafted application on a device on the network. To exploit the vulnerability, an unauthenticated attacker would be required to use MS-NRPC to connect to a domain controller to obtain domain administrator access. Microsoft is ad ... An elevation of privilege vulnerability exists when an attacker establishes a vulnerable Netlogon secure channel connection to a domain controller, using the Netlogon Remote Protocol (MS-NRPC). An attacker who successfully exploited the vulnerability could run a specially crafted application on a device on the network. To exploit the vulnerability, an unauthenticated attacker would be required to use MS-NRPC to connect to a domain controller to obtain domain administrator access. Microsoft is addressing the vulnerability in a phased two-part rollout. These updates address the vulnerability by modifying how Netlogon handles the usage of Netlogon secure channels. For guidelines on how to manage the changes required for this vulnerability and more information on the phased rollout, see How to manage the changes in Netlogon secure channel connections associated with CVE-2020-1472 (updated September 28, 2020). When the second phase of Windows updates become available in Q1 2021, customers will be notified via a revision to this security vulnerability. If you wish to be notified when these updates are released, we recommend that you register for the security notifications mailer to be alerted of content changes to this advisory. See Microsoft Technical Security Notifications.

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A flaw was found in Samba. The smbd service daemon does not pick up group membership changes when re-authenticating an expired SMB session. This issue can expose file shares until clients disconnect and then connect again.

The MS-RPC functionality in smbd in Samba 3.0.0 through 3.0.25rc3 allows remote attackers to execute arbitrary commands via shell metacharacters involving the (1) SamrChangePassword function, when the "username map script" smb.conf option is enabled, and allows remote authenticated users to execute commands via shell metacharacters involving other MS-RPC functions in the (2) remote printer and (3) file share management.

Samba since version 3.5.0 and before 4.6.4, 4.5.10 and 4.4.14 is vulnerable to remote code execution vulnerability, allowing a malicious client to upload a shared library to a writable share, and then cause the server to load and execute it.

In Samba, GnuTLS gnutls_rnd() can fail and give predictable random values.

Samba does not validate the Validated-DNS-Host-Name right for the dNSHostName attribute which could permit unprivileged users to write it.

MaxQueryDuration not honoured in Samba AD DC LDAP

The Netlogon server implementation in smbd in Samba 3.5.x and 3.6.x before 3.6.25, 4.0.x before 4.0.25, 4.1.x before 4.1.17, and 4.2.x before 4.2.0rc5 performs a free operation on an uninitialized stack pointer, which allows remote attackers to execute arbitrary code via crafted Netlogon packets that use the ServerPasswordSet RPC API, as demonstrated by packets reaching the _netr_ServerPasswordSet function in rpc_server/netlogon/srv_netlog_nt.c.

The Samba vfs_fruit module uses extended file attributes (EA, xattr) to provide "...enhanced compatibility with Apple SMB clients and interoperability with a Netatalk 3 AFP fileserver." Samba versions prior to 4.13.17, 4.14.12 and 4.15.5 with vfs_fruit configured allow out-of-bounds heap read and write via specially crafted extended file attributes. A remote attacker with write access to extended file attributes can execute arbitrary code with the privileges of smbd, typically root.

Heimdal before 7.4 allows remote attackers to impersonate services with Orpheus' Lyre attacks because it obtains service-principal names in a way that violates the Kerberos 5 protocol specification. In _krb5_extract_ticket() the KDC-REP service name must be obtained from the encrypted version stored in 'enc_part' instead of the unencrypted version stored in 'ticket'. Use of the unencrypted version provides an opportunity for successful server impersonation and other attacks. NOTE: this CVE is on ... Heimdal before 7.4 allows remote attackers to impersonate services with Orpheus' Lyre attacks because it obtains service-principal names in a way that violates the Kerberos 5 protocol specification. In _krb5_extract_ticket() the KDC-REP service name must be obtained from the encrypted version stored in 'enc_part' instead of the unencrypted version stored in 'ticket'. Use of the unencrypted version provides an opportunity for successful server impersonation and other attacks. NOTE: this CVE is only for Heimdal and other products that embed Heimdal code; it does not apply to other instances in which this part of the Kerberos 5 protocol specification is violated.

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smbd in Samba before 4.4.10 and 4.5.x before 4.5.6 has a denial of service vulnerability (fd_open_atomic infinite loop with high CPU usage and memory consumption) due to wrongly handling dangling symlinks.

Samba before 4.7.3 might allow remote attackers to obtain sensitive information by leveraging failure of the server to clear allocated heap memory.

Use-after-free vulnerability in Samba 4.x before 4.7.3 allows remote attackers to execute arbitrary code via a crafted SMB1 request.

Samba version 4.0.0 up to 4.5.2 is vulnerable to privilege elevation due to incorrect handling of the PAC (Privilege Attribute Certificate) checksum. A remote, authenticated, attacker can cause the winbindd process to crash using a legitimate Kerberos ticket. A local service with access to the winbindd privileged pipe can cause winbindd to cache elevated access permissions.

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).

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 krb5_pac_parse in lib/krb5/krb/pac.c. Heimdal before 7.7.1 has "a similar bug."

libcli/smb/smbXcli_base.c in Samba 4.x before 4.2.14, 4.3.x before 4.3.11, and 4.4.x before 4.4.5 allows man-in-the-middle attackers to bypass a client-signing protection mechanism, and consequently spoof SMB2 and SMB3 servers, via the (1) SMB2_SESSION_FLAG_IS_GUEST or (2) SMB2_SESSION_FLAG_IS_NULL flag.

vfs.c in smbd in Samba 3.x and 4.x before 4.1.22, 4.2.x before 4.2.7, and 4.3.x before 4.3.3, when share names with certain substring relationships exist, allows remote attackers to bypass intended file-access restrictions via a symlink that points outside of a share.

The SMB1 implementation in smbd in Samba 3.x and 4.x before 4.1.23, 4.2.x before 4.2.9, 4.3.x before 4.3.6, and 4.4.x before 4.4.0rc4 allows remote authenticated users to modify arbitrary ACLs by using a UNIX SMB1 call to create a symlink, and then using a non-UNIX SMB1 call to write to the ACL content.

The owner_set function in smbcacls.c in smbcacls in Samba 4.0.x before 4.0.16 and 4.1.x before 4.1.6 removes an ACL during use of a --chown or --chgrp option, which allows remote attackers to bypass intended access restrictions in opportunistic circumstances by leveraging an unintended administrative change.

Samba 4.x before 4.2.11, 4.3.x before 4.3.8, and 4.4.x before 4.4.2 does not verify X.509 certificates from TLS servers, which allows man-in-the-middle attackers to spoof LDAPS and HTTPS servers and obtain sensitive information via a crafted certificate.

Samba 3.x and 4.x before 4.2.11, 4.3.x before 4.3.8, and 4.4.x before 4.4.2 does not properly implement the DCE-RPC layer, which allows remote attackers to perform protocol-downgrade attacks, cause a denial of service (application crash or CPU consumption), or possibly execute arbitrary code on a client system via unspecified vectors.

The SMB1 protocol implementation in Samba 4.x before 4.2.11, 4.3.x before 4.3.8, and 4.4.x before 4.4.2 does not recognize the "server signing = mandatory" setting, which allows man-in-the-middle attackers to spoof SMB servers by modifying the client-server data stream.

The samldb_check_user_account_control_acl function in dsdb/samdb/ldb_modules/samldb.c in Samba 4.x before 4.1.22, 4.2.x before 4.2.7, and 4.3.x before 4.3.3 does not properly check for administrative privileges during creation of machine accounts, which allows remote authenticated users to bypass intended access restrictions by leveraging the existence of a domain with both a Samba DC and a Windows DC, a similar issue to CVE-2015-2535.

NetBIOS name services daemon (nmbd) in Samba 4.0.x before 4.0.21 and 4.1.x before 4.1.11 allows remote attackers to execute arbitrary code via unspecified vectors that modify heap memory, involving a sizeof operation on an incorrect variable in the unstrcpy macro in string_wrappers.h.

The NTLMSSP authentication implementation in Samba 3.x and 4.x before 4.2.11, 4.3.x before 4.3.8, and 4.4.x before 4.4.2 allows man-in-the-middle attackers to perform protocol-downgrade attacks by modifying the client-server data stream to remove application-layer flags or encryption settings, as demonstrated by clearing the NTLMSSP_NEGOTIATE_SEAL or NTLMSSP_NEGOTIATE_SIGN option to disrupt LDAP security.

Samba 3.6.6 through 3.6.23, 4.0.x before 4.0.18, and 4.1.x before 4.1.8, when a certain vfs shadow copy configuration is enabled, does not properly initialize the SRV_SNAPSHOT_ARRAY response field, which allows remote authenticated users to obtain potentially sensitive information from process memory via a (1) FSCTL_GET_SHADOW_COPY_DATA or (2) FSCTL_SRV_ENUMERATE_SNAPSHOTS request.

The MS-SAMR and MS-LSAD protocol implementations in Samba 3.x and 4.x before 4.2.11, 4.3.x before 4.3.8, and 4.4.x before 4.4.2 mishandle DCERPC connections, which allows man-in-the-middle attackers to perform protocol-downgrade attacks and impersonate users by modifying the client-server data stream, aka "BADLOCK."

The internal DNS server in Samba 4.x before 4.1.23, 4.2.x before 4.2.9, 4.3.x before 4.3.6, and 4.4.x before 4.4.0rc4, when an AD DC is configured, allows remote authenticated users to cause a denial of service (out-of-bounds read) or possibly obtain sensitive information from process memory by uploading a crafted DNS TXT record.

The internal DNS server in Samba 4.x before 4.0.18 does not check the QR field in the header section of an incoming DNS message before sending a response, which allows remote attackers to cause a denial of service (CPU and bandwidth consumption) via a forged response packet that triggers a communication loop, a related issue to CVE-1999-0103.

The sys_recvfrom function in nmbd in Samba 3.6.x before 3.6.24, 4.0.x before 4.0.19, and 4.1.x before 4.1.9 allows remote attackers to cause a denial of service (infinite loop and CPU consumption) via a malformed UDP packet.

Samba 3.x and 4.x before 4.1.22, 4.2.x before 4.2.7, and 4.3.x before 4.3.3 supports connections that are encrypted but unsigned, which allows man-in-the-middle attackers to conduct encrypted-to-unencrypted downgrade attacks by modifying the client-server data stream, related to clidfs.c, libsmb_server.c, and smbXcli_base.c.

The LDAP server in the AD domain controller in Samba 4.x before 4.1.22 does not check return values to ensure successful ASN.1 memory allocation, which allows remote attackers to cause a denial of service (memory consumption and daemon crash) via crafted packets.

The ldb_wildcard_compare function in ldb_match.c in ldb before 1.1.24, as used in the AD LDAP server in Samba 4.x before 4.1.22, 4.2.x before 4.2.7, and 4.3.x before 4.3.3, mishandles certain zero values, which allows remote attackers to cause a denial of service (infinite loop) via crafted packets.

The shadow_copy2_get_shadow_copy_data function in modules/vfs_shadow_copy2.c in Samba 3.x and 4.x before 4.1.22, 4.2.x before 4.2.7, and 4.3.x before 4.3.3 does not verify that the DIRECTORY_LIST access right has been granted, which allows remote attackers to access snapshots by visiting a shadow copy directory.

The NETLOGON service in Samba 3.x and 4.x before 4.2.11, 4.3.x before 4.3.8, and 4.4.x before 4.4.2, when a domain controller is configured, allows remote attackers to spoof the computer name of a secure channel's endpoint, and obtain sensitive session information, by running a crafted application and leveraging the ability to sniff network traffic, a related issue to CVE-2015-0005.

The push_ascii function in smbd in Samba 3.6.x before 3.6.24, 4.0.x before 4.0.19, and 4.1.x before 4.1.9 allows remote authenticated users to cause a denial of service (memory corruption and daemon crash) via an attempt to read a Unicode pathname without specifying use of Unicode, leading to a character-set conversion failure that triggers an invalid pointer dereference.

Samba 4.0.x before 4.0.24, 4.1.x before 4.1.16, and 4.2.x before 4.2rc4, when an Active Directory Domain Controller (AD DC) is configured, allows remote authenticated users to set the LDB userAccountControl UF_SERVER_TRUST_ACCOUNT bit, and consequently gain privileges, by leveraging delegation of authority for user-account or computer-account creation.

Samba 3.x before 3.6.23, 4.0.x before 4.0.16, and 4.1.x before 4.1.6 does not enforce the password-guessing protection mechanism for all interfaces, which makes it easier for remote attackers to obtain access via brute-force ChangePasswordUser2 (1) SAMR or (2) RAP attempts.

The bundled LDAP client library in Samba 3.x and 4.x before 4.2.11, 4.3.x before 4.3.8, and 4.4.x before 4.4.2 does not recognize the "client ldap sasl wrapping" setting, which allows man-in-the-middle attackers to perform LDAP protocol-downgrade attacks by modifying the client-server data stream.