CVE-2016-6581

Severity Score

7.5

*CVSS v3

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

A HTTP/2 implementation built using any version of the Python HPACK library between v1.0.0 and v2.2.0 could be targeted for a denial of service attack, specifically a so-called "HPACK Bomb" attack. This attack occurs when an attacker inserts a header field that is exactly the size of the HPACK dynamic header table into the dynamic header table. The attacker can then send a header block that is simply repeated requests to expand that field in the dynamic table. This can lead to a gigantic compression ratio of 4,096 or better, meaning that 16kB of data can decompress to 64MB of data on the target machine.

Una implementación de HTTP/2 construida usando cualquier versión de la librería de Python HPACK entre las versiones v1.0.0 y v2.2.0 podría ser atacada por un ataque de denegación de servicio, especialmente un ataque llamado "HPACK Bomb". Este ataque ocurre cuando un atacante inserta un campo de cabecera que es exactamente del tamaño de la tabla de cabecera dinámica HPACK dentro de la tabla de cabecera dinámica. El atacante puede entonces enviar un bloque de cabecera que simplemente repita solicitudes para expandir ese campo en la tabla dinámica. Esto puede conducir a un ratio de compresión gigante de 4,096 o mayor, significando que 16kB de datos pueden descomprimirse a 64MB de datos en la máquina objetivo.

*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

Complete

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2016-08-03 CVE Reserved
2017-01-10 CVE Published
2023-03-08 EPSS Updated
2024-08-06 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-399: Resource Management Errors

CAPEC

References (2)

URL	Tag	Source
http://www.securityfocus.com/bid/92315	Third Party Advisory

URL	Date	SRC

URL	Date	SRC

URL	Date	SRC
https://python-hyper.org/hpack/en/latest/security/CVE-2016-6581.html	2017-01-27

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Python Search vendor "Python"		Hpack Search vendor "Python" for product "Hpack"				1.0 Search vendor "Python" for product "Hpack" and version "1.0"		-		Affected
Python Search vendor "Python"		Hpack Search vendor "Python" for product "Hpack"				2.0 Search vendor "Python" for product "Hpack" and version "2.0"		-		Affected
Python Search vendor "Python"		Hpack Search vendor "Python" for product "Hpack"				2.0.1 Search vendor "Python" for product "Hpack" and version "2.0.1"		-		Affected
Python Search vendor "Python"		Hpack Search vendor "Python" for product "Hpack"				2.1.1 Search vendor "Python" for product "Hpack" and version "2.1.1"		-		Affected
Python Search vendor "Python"		Hpack Search vendor "Python" for product "Hpack"				2.2 Search vendor "Python" for product "Hpack" and version "2.2"		-		Affected
Python Search vendor "Python"		Hyper Search vendor "Python" for product "Hyper"				0.4 Search vendor "Python" for product "Hyper" and version "0.4"		-		Affected
Python Search vendor "Python"		Hyper Search vendor "Python" for product "Hyper"				0.6 Search vendor "Python" for product "Hyper" and version "0.6"		-		Affected