CVE-2016-6581
Apache Python HPACK HTTP2 Denial of Service Vulnerability
Description
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.
INFO
Published Date :
Jan. 10, 2017, 3:59 p.m.
Last Modified :
Nov. 21, 2024, 2:56 a.m.
Source :
[email protected]
Remotely Exploitable :
Yes !
Impact Score :
3.6
Exploitability Score :
3.9
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2016-6581.
| URL | Resource |
|---|---|
| http://www.securityfocus.com/bid/92315 | Third Party Advisory VDB Entry |
| https://python-hyper.org/hpack/en/latest/security/CVE-2016-6581.html | Mitigation Vendor Advisory |
| http://www.securityfocus.com/bid/92315 | Third Party Advisory VDB Entry |
| https://python-hyper.org/hpack/en/latest/security/CVE-2016-6581.html | Mitigation Vendor Advisory |
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2016-6581 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2016-6581 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Nov. 21, 2024
Action Type Old Value New Value Added Reference http://www.securityfocus.com/bid/92315 Added Reference https://python-hyper.org/hpack/en/latest/security/CVE-2016-6581.html -
CVE Modified by [email protected]
May. 14, 2024
Action Type Old Value New Value -
Modified Analysis by [email protected]
Jan. 27, 2017
Action Type Old Value New Value Changed CPE Configuration OR *cpe:2.3:a:python_software_foundation:hpack:1.0:*:*:*:*:*:*:* *cpe:2.3:a:python_software_foundation:hpack:2.0:*:*:*:*:*:*:* *cpe:2.3:a:python_software_foundation:hpack:2.0.1:*:*:*:*:*:*:* *cpe:2.3:a:python_software_foundation:hpack:2.1.1:*:*:*:*:*:*:* *cpe:2.3:a:python_software_foundation:hpack:2.2:*:*:*:*:*:*:* *cpe:2.3:a:python_software_foundation:hyper:0.4:*:*:*:*:*:*:* *cpe:2.3:a:python_software_foundation:hyper:0.6:*:*:*:*:*:*:* OR *cpe:2.3:a:python:hpack:1.0:*:*:*:*:*:*:* *cpe:2.3:a:python:hpack:2.0:*:*:*:*:*:*:* *cpe:2.3:a:python:hpack:2.0.1:*:*:*:*:*:*:* *cpe:2.3:a:python:hpack:2.1.1:*:*:*:*:*:*:* *cpe:2.3:a:python:hpack:2.2:*:*:*:*:*:*:* *cpe:2.3:a:python:hyper:0.4:*:*:*:*:*:*:* *cpe:2.3:a:python:hyper:0.6:*:*:*:*:*:*:* -
CVE Modified by [email protected]
Jan. 13, 2017
Action Type Old Value New Value Changed Description A HTTP/2 implementation built using any version of the Python HPACK library between v1.0.0 and v2.2.0 could be targetted 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. 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. -
Initial Analysis by [email protected]
Jan. 11, 2017
Action Type Old Value New Value Added CVSS V2 (AV:N/AC:L/Au:N/C:N/I:N/A:C) Added CVSS V3 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Changed Reference Type http://www.securityfocus.com/bid/92315 No Types Assigned http://www.securityfocus.com/bid/92315 Third Party Advisory, VDB Entry Changed Reference Type https://python-hyper.org/hpack/en/latest/security/CVE-2016-6581.html No Types Assigned https://python-hyper.org/hpack/en/latest/security/CVE-2016-6581.html Mitigation, Vendor Advisory Added CWE CWE-399 Added CPE Configuration OR *cpe:2.3:a:python_software_foundation:hpack:1.0:*:*:*:*:*:*:* *cpe:2.3:a:python_software_foundation:hpack:2.0:*:*:*:*:*:*:* *cpe:2.3:a:python_software_foundation:hpack:2.0.1:*:*:*:*:*:*:* *cpe:2.3:a:python_software_foundation:hpack:2.1.1:*:*:*:*:*:*:* *cpe:2.3:a:python_software_foundation:hpack:2.2:*:*:*:*:*:*:* *cpe:2.3:a:python_software_foundation:hyper:0.4:*:*:*:*:*:*:* *cpe:2.3:a:python_software_foundation:hyper:0.6:*:*:*:*:*:*:*
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2016-6581 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2016-6581
weaknesses.
Exploit Prediction
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.
0.08 }} -0.01%
score
0.37142
percentile