CVE-2016-7796

systemd: freeze when PID 1 receives a zero-length message over notify socket

Severity Score

5.5

*CVSS v3

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

The manager_dispatch_notify_fd function in systemd allows local users to cause a denial of service (system hang) via a zero-length message received over a notify socket, which causes an error to be returned and the notification handler to be disabled.

La función manager_dispatch_notify_fd en systemd permite a usuarios locales provocar una denegación de servicio (colgado de sistema) a través de un mensaje de longitud cero recibido sobre una notificación de encaje, lo que provoca que se devuelva un error y que el controlador de notificación se desactive.

A flaw was found in the way systemd handled empty notification messages. A local attacker could use this flaw to make systemd freeze its execution, preventing further management of system services, system shutdown, or zombie process collection via systemd.

The systemd packages contain systemd, a system and service manager for Linux, compatible with the SysV and LSB init scripts. It provides aggressive parallelism capabilities, uses socket and D-Bus activation for starting services, offers on-demand starting of daemons, and keeps track of processes using Linux cgroups.

*Credits: N/A

CVSS Scores

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Attack Vector

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

High

Attack Vector

Local

Attack Complexity

Low

Authentication

None

Confidentiality

None

Integrity

None

Availability

Complete

Attack Vector

Local

Attack Complexity

Low

Authentication

None

Confidentiality

None

Integrity

Partial

Availability

Complete

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2016-09-09 CVE Reserved
2016-10-13 CVE Published
2024-08-06 CVE Updated
2024-08-06 First Exploit
2025-03-30 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date

CWE

CWE-20: Improper Input Validation
CWE-253: Incorrect Check of Function Return Value

CAPEC

References (11)

URL	Tag	Source
http://www.openwall.com/lists/oss-security/2016/09/30/1	Mailing List
http://www.securityfocus.com/bid/93250	Third Party Advisory
http://www.securitytracker.com/id/1037320	Vdb Entry

URL	Date	SRC
https://github.com/systemd/systemd/issues/4234#issuecomment-250441246	2024-08-06
https://www.agwa.name/blog/post/how_to_crash_systemd_in_one_tweet	2024-08-06

URL	Date	SRC

URL	Date	SRC
http://lists.opensuse.org/opensuse-security-announce/2016-10/msg00015.html	2023-09-12
http://lists.opensuse.org/opensuse-security-announce/2016-10/msg00016.html	2023-09-12
http://rhn.redhat.com/errata/RHSA-2017-0003.html	2023-09-12
https://bugzilla.redhat.com/show_bug.cgi?id=1381911	2017-01-03
https://rhn.redhat.com/errata/RHBA-2015-2092.html	2023-09-12
https://access.redhat.com/security/cve/CVE-2016-7796	2017-01-03

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Systemd Project Search vendor "Systemd Project"		Systemd Search vendor "Systemd Project" for product "Systemd"				209 Search vendor "Systemd Project" for product "Systemd" and version "209"		-		Affected
Systemd Project Search vendor "Systemd Project"		Systemd Search vendor "Systemd Project" for product "Systemd"				213 Search vendor "Systemd Project" for product "Systemd" and version "213"		-		Affected
Systemd Project Search vendor "Systemd Project"		Systemd Search vendor "Systemd Project" for product "Systemd"				214 Search vendor "Systemd Project" for product "Systemd" and version "214"		-		Affected
Systemd Project Search vendor "Systemd Project"		Systemd Search vendor "Systemd Project" for product "Systemd"				229 Search vendor "Systemd Project" for product "Systemd" and version "229"		-		Affected
Novell Search vendor "Novell"		Suse Linux Enterprise Software Development Kit Search vendor "Novell" for product "Suse Linux Enterprise Software Development Kit"				12.0 Search vendor "Novell" for product "Suse Linux Enterprise Software Development Kit" and version "12.0"		sp1		Affected
Novell Search vendor "Novell"		Suse Linux Enterprise Desktop Search vendor "Novell" for product "Suse Linux Enterprise Desktop"				12 Search vendor "Novell" for product "Suse Linux Enterprise Desktop" and version "12"		sp1		Affected
Novell Search vendor "Novell"		Suse Linux Enterprise Server Search vendor "Novell" for product "Suse Linux Enterprise Server"				12.0 Search vendor "Novell" for product "Suse Linux Enterprise Server" and version "12.0"		ltss		Affected
Novell Search vendor "Novell"		Suse Linux Enterprise Server Search vendor "Novell" for product "Suse Linux Enterprise Server"				12.0 Search vendor "Novell" for product "Suse Linux Enterprise Server" and version "12.0"		sp1		Affected
Novell Search vendor "Novell"		Suse Linux Enterprise Server For Sap Search vendor "Novell" for product "Suse Linux Enterprise Server For Sap"				12.0 Search vendor "Novell" for product "Suse Linux Enterprise Server For Sap" and version "12.0"		-		Affected
Redhat Search vendor "Redhat"		Enterprise Linux Desktop Search vendor "Redhat" for product "Enterprise Linux Desktop"				7.0 Search vendor "Redhat" for product "Enterprise Linux Desktop" and version "7.0"		-		Affected
Redhat Search vendor "Redhat"		Enterprise Linux Hpc Node Search vendor "Redhat" for product "Enterprise Linux Hpc Node"				7.0 Search vendor "Redhat" for product "Enterprise Linux Hpc Node" and version "7.0"		-		Affected
Redhat Search vendor "Redhat"		Enterprise Linux Server Search vendor "Redhat" for product "Enterprise Linux Server"				7.0 Search vendor "Redhat" for product "Enterprise Linux Server" and version "7.0"		-		Affected
Redhat Search vendor "Redhat"		Enterprise Linux Workstation Search vendor "Redhat" for product "Enterprise Linux Workstation"				7.0 Search vendor "Redhat" for product "Enterprise Linux Workstation" and version "7.0"		-		Affected