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GHSA-gwvm-45gx-3cf8 CVE-2018-25091 PYSEC-2023-207

Authorization Header forwarded on redirect

Medium PyPI
Severity
0.0 / 10
Medium · CVSS 4.0
Exploit chance (EPSS)
0.59%
Chance of exploitation in the next 30 days. Higher than 48.42% of scored vulnerabilities.
Known exploited
No
Not in CISA's catalog
Weakness
CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
CWE-601 URL Redirection to Untrusted Site ('Open Redirect')
Fix
1.24.2
Upgrade urllib3 to this version or later

Description

urllib3 before 1.24.2 does not remove the authorization HTTP header when following a cross-origin redirect (i.e., a redirect that differs in host, port, or scheme). This can allow for credentials in the authorization header to be exposed to unintended hosts or transmitted in cleartext. NOTE: this issue exists because of an incomplete fix for CVE-2018-20060 (which was case-sensitive).

Affected versions

PyPI

PackageVulnerableFixed in
urllib3
< 1.24.2
1.24.2
urllib3
< 1.24.2
1.24.2

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

urllib3 PyPI → 1.24.2

pip
pip install --upgrade "urllib3>=1.24.2"
poetry
poetry add "urllib3>=1.24.2"
uv
uv add "urllib3>=1.24.2"

Severity breakdown

CVSS 4.0 0.0

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

Attack vector
Network
Attack complexity
Low
Attack requirements
None
Privileges required
None
User interaction
Passive
Confidentiality (vulnerable system)
None
Integrity (vulnerable system)
None
Availability (vulnerable system)
None
Confidentiality (subsequent systems)
Low
Integrity (subsequent systems)
Low
Availability (subsequent systems)
None

CVSS 3.1 6.1

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

Weakness

CWE-200: Exposure of Sensitive Information to an Unauthorized Actor

The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.

How to prevent it
  • Architecture and Design: Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.

CWE-601: URL Redirection to Untrusted Site ('Open Redirect')

The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.

How to prevent it
  • Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright. Use a list of approved URLs or domains to be used for redirection.
  • Architecture and Design: Use an intermediate disclaimer page that provides the user with a clear warning that they are leaving the current site. Implement a long timeout before the redirect occurs, or force the user to click on the link. Be careful to avoid XSS problems (CWE-79) when generating the disclaimer page.
  • Architecture and Design: When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs. For example, ID 1 could map to "/login.asp" and ID 2 could map to "http://www.example.com/". Features such as the ESAPI AccessReferenceMap [REF-45] provide this capability.
  • Architecture and Design: Ensure that no externally-supplied requests are honored by requiring that all redirect requests include a unique nonce generated by the application [REF-483]. Be sure that the nonce is not predictable (CWE-330).
  • Architecture and Design, Implementation: Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls. Many open redirect problems occur because the programmer assumed that certain inputs could not be modified, such as cookies and hidden form fields.
  • Operation: Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth [REF-1481].

References

Timeline

  1. Published
  2. Last updated by the source
  3. Latest EPSS score
AdvisorySeverityWhy it's related
GHSA-vxq7-64xx-v4gw
urllib3: HTTPResponse.stream()/read_chunked() buffers an unbounded chunk-size line into memory
High Also affects urllib3
GHSA-gh4c-6fx4-qh6g
urllib3: Chunked Deflate streaming can enter an infinite loop
Medium Also affects urllib3
GHSA-8988-9cw3-xx77
urllib3: HTTPS proxy TLS configuration may be ignored or overridden
High Also affects urllib3
GHSA-mf9v-mfxr-j63j
urllib3: Decompression-bomb safeguards bypassed in parts of the streaming API
High Also affects urllib3
GHSA-qccp-gfcp-xxvc
urllib3: Sensitive headers forwarded across origins in proxied low-level redirects
High Also affects urllib3
GHSA-38jv-5279-wg99
Decompression-bomb safeguards bypassed when following HTTP redirects (streaming API)
High Also affects urllib3
GHSA-2xpw-w6gg-jr37
urllib3 streaming API improperly handles highly compressed data
High Also affects urllib3
GHSA-gm62-xv2j-4w53
urllib3 allows an unbounded number of links in the decompression chain
High Also affects urllib3
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