CVE-2019-6477

TCP-pipelined queries can bypass tcp-clients limit

Severity Score

7.5

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

With pipelining enabled each incoming query on a TCP connection requires a similar resource allocation to a query received via UDP or via TCP without pipelining enabled. A client using a TCP-pipelined connection to a server could consume more resources than the server has been provisioned to handle. When a TCP connection with a large number of pipelined queries is closed, the load on the server releasing these multiple resources can cause it to become unresponsive, even for queries that can be answered authoritatively or from cache. (This is most likely to be perceived as an intermittent server problem).

Con pipelining habilitada, cada consulta entrante en una conexión TCP requiere una asignación de recursos similar a una consulta recibida por medio de UDP o TCP sin pipelining habilitada. Un cliente que utiliza una conexión canalizada por TCP a un servidor podría consumir más recursos de los que el servidor ha sido provisionado para manejar. Cuando una conexión TCP con un gran número de consultas canalizadas se cierra, la carga en el servidor que libera estos múltiples recursos puede causar que no responda, inclusive para consultas que pueden ser respondidas con autoridad o desde la memoria caché. (Esto es muy probable que sea percibido como un problema de servidor intermitente).

A flaw was found in the way bind limited the number of TCP clients that can be connected at any given time. A remote attacker could use one TCP client to send a large number of DNS requests over a single connection, causing exhaustion of the pool of file descriptors available to named, and potentially affecting network connections and the management of files such as log files or zone journal files.

*Credits: N/A

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Attack Vector

Network

Attack Complexity

Low

Authentication

None

Confidentiality

None

Integrity

None

Availability

Partial

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2019-01-16 CVE Reserved
2019-11-21 CVE Published
2024-09-16 CVE Updated
2024-11-19 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-400: Uncontrolled Resource Consumption

CAPEC

References (10)

URL	Tag	Source
https://kb.isc.org/docs/cve-2019-6477	Third Party Advisory
https://support.f5.com/csp/article/K15840535?utm_source=f5support&amp%3Butm_medium=RSS	X_refsource_confirm
https://www.synology.com/security/advisory/Synology_SA_19_39	Third Party Advisory

URL	Date	SRC

URL	Date	SRC

URL	Date	SRC
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00041.html	2023-11-07
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00044.html	2023-11-07
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L3DEMNZMKR57VQJCG5ZN55ZGTQRL2TFQ	2023-11-07
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XGURMGQHX45KR4QDRCSUQHODUFOGNGAN	2023-11-07
https://www.debian.org/security/2020/dsa-4689	2023-11-07
https://access.redhat.com/security/cve/CVE-2019-6477	2020-04-28
https://bugzilla.redhat.com/show_bug.cgi?id=1773617	2020-04-28

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Isc Search vendor "Isc"		Bind Search vendor "Isc" for product "Bind"				>= 9.11.7 <= 9.11.12 Search vendor "Isc" for product "Bind" and version " >= 9.11.7 <= 9.11.12"		-		Affected
Isc Search vendor "Isc"		Bind Search vendor "Isc" for product "Bind"				>= 9.14.1 <= 9.14.7 Search vendor "Isc" for product "Bind" and version " >= 9.14.1 <= 9.14.7"		-		Affected
Isc Search vendor "Isc"		Bind Search vendor "Isc" for product "Bind"				>= 9.15.0 <= 9.15.5 Search vendor "Isc" for product "Bind" and version " >= 9.15.0 <= 9.15.5"		-		Affected
Isc Search vendor "Isc"		Bind Search vendor "Isc" for product "Bind"				9.11.5 Search vendor "Isc" for product "Bind" and version "9.11.5"		s6, supported_preview		Affected
Isc Search vendor "Isc"		Bind Search vendor "Isc" for product "Bind"				9.11.6 Search vendor "Isc" for product "Bind" and version "9.11.6"		p1		Affected
Isc Search vendor "Isc"		Bind Search vendor "Isc" for product "Bind"				9.11.6 Search vendor "Isc" for product "Bind" and version "9.11.6"		rc1		Affected
Isc Search vendor "Isc"		Bind Search vendor "Isc" for product "Bind"				9.11.12 Search vendor "Isc" for product "Bind" and version "9.11.12"		s1, supported_preview		Affected
Isc Search vendor "Isc"		Bind Search vendor "Isc" for product "Bind"				9.12.4 Search vendor "Isc" for product "Bind" and version "9.12.4"		p1		Affected
Isc Search vendor "Isc"		Bind Search vendor "Isc" for product "Bind"				9.12.4 Search vendor "Isc" for product "Bind" and version "9.12.4"		p2		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				30 Search vendor "Fedoraproject" for product "Fedora" and version "30"		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				31 Search vendor "Fedoraproject" for product "Fedora" and version "31"		-		Affected