National Vulnerability Database

National Vulnerability Database

National Vulnerability
Database

CVE-2016-6581 Detail

Current 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.

Source:  MITRE
View Analysis Description

Impact

CVSS v3.0 Severity and Metrics:

Base Score: 7.5 HIGH
Vector: AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (V3 legend)
Impact Score: 3.6
Exploitability Score: 3.9


Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): None
Integrity (I): None
Availability (A): High

CVSS v2.0 Severity and Metrics:

Base Score: 7.8 HIGH
Vector: (AV:N/AC:L/Au:N/C:N/I:N/A:C) (V2 legend)
Impact Subscore: 6.9
Exploitability Subscore: 10.0


Access Vector (AV): Network
Access Complexity (AC): Insufficient_Info
Authentication (AU): None
Confidentiality (C): None
Integrity (I): None
Availability (A): Complete
Additional Information:
Allows disruption of service

References to Advisories, Solutions, and Tools

By selecting these links, you will be leaving NIST webspace. We have provided these links to other web sites because they may have information that would be of interest to you. No inferences should be drawn on account of other sites being referenced, or not, from this page. There may be other web sites that are more appropriate for your purpose. NIST does not necessarily endorse the views expressed, or concur with the facts presented on these sites. Further, NIST does not endorse any commercial products that may be mentioned on these sites. Please address comments about this page to nvd@nist.gov.

Hyperlink 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

Technical Details

Vulnerability Type (View All)

  • Resource Management Errors (CWE-399)

Known Affected Software Configurations Switch to CPE 2.2

Configuration 1 ( hide )
 cpe:2.3:a:python:hpack:1.0:*:*:*:*:*:*:*
     Show Matching CPE(s)
 cpe:2.3:a:python:hpack:2.0:*:*:*:*:*:*:*
     Show Matching CPE(s)
 cpe:2.3:a:python:hpack:2.0.1:*:*:*:*:*:*:*
     Show Matching CPE(s)
 cpe:2.3:a:python:hpack:2.1.1:*:*:*:*:*:*:*
     Show Matching CPE(s)
 cpe:2.3:a:python:hpack:2.2:*:*:*:*:*:*:*
     Show Matching CPE(s)
 cpe:2.3:a:python:hyper:0.4:*:*:*:*:*:*:*
     Show Matching CPE(s)
 cpe:2.3:a:python:hyper:0.6:*:*:*:*:*:*:*
     Show Matching CPE(s)


Change History

3 change records found - show changes

Quick Info

CVE Dictionary Entry:
CVE-2016-6581
NVD Published Date:
01/10/2017
NVD Last Modified:
01/27/2017