Synology-SA-21:29 Samba

Abstract

CVE-2016-2124 and CVE-2020-25717 allow remote authenticated users and man-in-the-middle attackers to obtain sensitive information and bypass security constraint via a susceptible version of Synology DiskStation Manager (DSM), Synology Router Manager (SRM) and SMB Service.

CVE-2020-25718, CVE-2020-25719, CVE-2020-25721, CVE-2020-25722, CVE-2021-3738 and CVE-2021-23192 allow remote authenticated users and man-in-the-middle attackers to bypass security constraint and conduct denial-of-service attacks via a susceptible version of Synology Directory Server.

Affected Products

Mitigation

None

Detail

• CVE-2020-25717

  • Severity: Important
  • CVSS3 Base Score: 8.1
  • CVSS3 Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
  • A flaw was found in the way Samba maps domain users to local users. An authenticated attacker could use this flaw to cause possible privilege escalation.

• CVE-2020-25718

  • Severity: Important
  • CVSS3 Base Score: 7.5
  • CVSS3 Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
  • A flaw was found in the way samba, as an Active Directory Domain Controller, is able to support an RODC (read-only domain controller). This would allow an RODC to print administrator tickets.

• CVE-2020-25719

  • Severity: Important
  • CVSS3 Base Score: 7.2
  • CVSS3 Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
  • A flaw was found in the way Samba, as an Active Directory Domain Controller, implemented Kerberos name-based authentication. The Samba AD DC, could become confused about the user a ticket represents if it did not strictly require a Kerberos PAC and always use the SIDs found within. The result could include total domain compromise.

• CVE-2020-25721

  • Severity: Important
  • CVSS3 Base Score: 7.4
  • CVSS3 Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L
  • Kerberos acceptors need easy access to stable AD identifiers (eg objectSid). Samba as an AD DC now provides a way for Linux applications to obtain a reliable SID (and samAccountName) in issued tickets.

• CVE-2020-25722

  • Severity: Important
  • CVSS3 Base Score: 8.8
  • CVSS3 Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
  • Multiple flaws were found in the way samba AD DC implemented access and conformance checking of stored data. An attacker could use this flaw to cause total domain compromise.

• CVE-2021-3738

  • Severity: Important
  • CVSS3 Base Score: 7.6
  • CVSS3 Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H
  • In DCE/RPC it is possible to share the handles (cookies for resource state) between multiple connections via a mechanism called 'association groups'. These handles can reference connections to our sam.ldb database. However while the database was correctly shared, the user credentials state was only pointed at, and when one connection within that association group ended, the database would be left pointing at an invalid 'struct session_info'. The most likely outcome here is a crash, but it is possible that the use-after-free could instead allow different user state to be pointed at and this might allow more privileged access.

• CVE-2016-2124

  • Severity: Moderate
  • CVSS3 Base Score: 5.3
  • CVSS3 Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
  • A flaw was found in the way samba implemented SMB1 authentication. An attacker could use this flaw to retrieve the plaintext password sent over the wire even if Kerberos authentication was required.

• CVE-2021-23192

  • Severity: Moderate
  • CVSS3 Base Score: 4.8
  • CVSS3 Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
  • A flaw was found in the way samba implemented DCE/RPC. If a client to a Samba server sent a very large DCE/RPC request, and chose to fragment it, an attacker could replace later fragments with their own data, bypassing the signature requirements.

Reference

• Samba Releases Security Updates
• CVE-2020-25717
• CVE-2020-25718
• CVE-2020-25719
• CVE-2020-25721
• CVE-2020-25722
• CVE-2021-3738
• CVE-2016-2124
• CVE-2021-23192

Revision