Attacker Value
Unknown
(0 users assessed)
Exploitability
Unknown
(0 users assessed)
User Interaction
None
Privileges Required
Low
Attack Vector
Network
0

CVE-2020-15811

Disclosure Date: September 02, 2020
Add MITRE ATT&CK tactics and techniques that apply to this CVE.

Description

An issue was discovered in Squid before 4.13 and 5.x before 5.0.4. Due to incorrect data validation, HTTP Request Splitting attacks may succeed against HTTP and HTTPS traffic. This leads to cache poisoning. This allows any client, including browser scripts, to bypass local security and poison the browser cache and any downstream caches with content from an arbitrary source. Squid uses a string search instead of parsing the Transfer-Encoding header to find chunked encoding. This allows an attacker to hide a second request inside Transfer-Encoding: it is interpreted by Squid as chunked and split out into a second request delivered upstream. Squid will then deliver two distinct responses to the client, corrupting any downstream caches.

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CVSS V3 Severity and Metrics
Base Score:
6.5 Medium
Impact Score:
3.6
Exploitability Score:
2.8
Vector:
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Attack Vector (AV):
Network
Attack Complexity (AC):
Low
Privileges Required (PR):
Low
User Interaction (UI):
None
Scope (S):
Unchanged
Confidentiality (C):
None
Integrity (I):
High
Availability (A):
None

General Information

Vendors

  • canonical,
  • debian,
  • fedoraproject,
  • opensuse,
  • squid-cache

Products

  • debian linux 10.0,
  • debian linux 9.0,
  • fedora 31,
  • fedora 32,
  • fedora 33,
  • leap 15.1,
  • leap 15.2,
  • squid,
  • ubuntu linux 16.04,
  • ubuntu linux 18.04,
  • ubuntu linux 20.04

References

Additional Info

Technical Analysis