CVE-2019-3843

It was discovered that a systemd service that uses DynamicUser property can create a SUID/SGID binary that would be allowed to run as the transient service UID/GID even after the service is terminated. A local attacker may use this flaw to access resources that will be owned by a potentially different service in the future, when the UID/GID will be recycled.

• SECURITY UPDATE: Privilege chaining vulnerability
  • debian/patches/CVE-2019-3843.patch: introduce functionality for blocking chmod() for suid/sgid files with new unit setting RestrictSUIDSGID=
  • CVE-2019-3843
• SECURITY UPDATE: Privilege chaining vulnerability
  • debian/patches/CVE-2019-3844.patch: imply NNP and SUID/SGID restriction for DynamicUser=yes service
  • CVE-2019-3844

These are all security issues fixed in the libsystemd0-249.4-2.2 package on the GA media of openSUSE Tumbleweed.

This update for systemd fixes the following issues:

Security issues fixed:

• CVE-2019-3842: Fixed a privilege escalation in pam_systemd which could be exploited by a local user (bsc#1132348).
• CVE-2019-6454: Fixed a denial of service via crafted D-Bus message (bsc#1125352).
• CVE-2019-3843, CVE-2019-3844: Fixed a privilege escalation where services with DynamicUser could gain new privileges or create SUID/SGID binaries (bsc#1133506, bsc#1133509).

Non-security issued fixed:

• logind: fix killing of scopes (bsc#1125604)
• namespace: make MountFlags=shared work again (bsc#1124122)
• rules: load drivers only on 'add' events (bsc#1126056)
• sysctl: Don't pass null directive argument to '%s' (bsc#1121563)
• systemd-coredump: generate a stack trace of all core dumps and log into the journal (jsc#SLE-5933)
• udevd: notify when max number value of children is reached only once per batch of events (bsc#1132400)
• sd-bus: bump message queue size again (bsc#1132721)
• Do not automatically online memory on s390x (bsc#1127557)
• Removed sg.conf (bsc#1036463)

This update for systemd fixes the following issues:

Security issues fixed:

• CVE-2019-3842: Fixed a privilege escalation in pam_systemd which could be exploited by a local user (bsc#1132348).
• CVE-2019-6454: Fixed a denial of service via crafted D-Bus message (bsc#1125352).
• CVE-2019-3843, CVE-2019-3844: Fixed a privilege escalation where services with DynamicUser could gain new privileges or create SUID/SGID binaries (bsc#1133506, bsc#1133509).

Non-security issued fixed:

• logind: fix killing of scopes (bsc#1125604)
• namespace: make MountFlags=shared work again (bsc#1124122)
• rules: load drivers only on 'add' events (bsc#1126056)
• sysctl: Don't pass null directive argument to '%s' (bsc#1121563)
• systemd-coredump: generate a stack trace of all core dumps and log into the journal (jsc#SLE-5933)
• udevd: notify when max number value of children is reached only once per batch of events (bsc#1132400)
• sd-bus: bump message queue size again (bsc#1132721)
• Do not automatically online memory on s390x (bsc#1127557)
• Removed sg.conf (bsc#1036463)

It was discovered that systemd incorrectly handled certain PIDFile files. A local attacker could possibly use this issue to trick systemd into killing privileged processes. This issue only affected Ubuntu 16.04 LTS. (CVE-2018-16888)

It was discovered that systemd incorrectly handled certain udevadm trigger commands. A local attacker could possibly use this issue to cause systemd to consume resources, leading to a denial of service. (CVE-2019-20386)

Jann Horn discovered that systemd incorrectly handled services that use the DynamicUser property. A local attacker could possibly use this issue to access resources owned by a different service in the future. This issue only affected Ubuntu 18.04 LTS. (CVE-2019-3843, CVE-2019-3844)

Tavis Ormandy discovered that systemd incorrectly handled certain Polkit queries. A local attacker could use this issue to cause systemd to crash, resulting in a denial of service, or possibly execute arbitrary code and escalate privileges. (CVE-2020-1712)