8.8 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
5 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
NONE
Availability Impact
NONE
AV:N/AC:L/Au:N/C:P/I:N/A:N
0.017 Low
EPSS
Percentile
87.4%
Web proxy auto-config (PAC) files are passed the full HTTPS URL in GET requests which may expose sensitive data.
CWE-212**: Improper Cross-boundary Removal of Sensitive Data -**CVE-2016-5134 (Google), CVE-2016-1801 (Apple)
Web proxy auto-configuration files (proxy.pac
) have access to the full URL including the path and parameters in HTTPS GET requests, which may expose sensitive data intended to be protected by HTTPS. This information is passed to the FindProxyForURL()
function in the proxy.pac
. The PAC file is often retrieved by the browser automatically using the WPAD protocol. An attacker in the position to conduct man-in-the-middle attacks may provide a malicious PAC file capable of exploiting the FindProxyForURL()
function to exfiltrate sensitive data.
An attacker who can provide a specially crafted PAC file can read URLs, including the path and query string, which may contain sensitive information intended to be protected by HTTPS.
Apply an update.
Apply the latest updates to your browser, see Vendor Information section below.
Users who are unable to or do not wish to update their browsers should consider the following workaround.
Disable WPAD.
If proxy auto-configuration is not necessary, consider disabling WPAD functionality for your browser.
This vendors listed below are suspected to be affected by the vulnerability. Other browser vendors not listed may be affected as well. The CERT/CC has no further evidence that any particular vendor is impacted unless marked Affected; vendors are encouraged to reach out to us to clarify their status.
877625
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Notified: July 27, 2016 Updated: August 04, 2016
Affected
We have not received a statement from the vendor.
We are not aware of further vendor information regarding this vulnerability.
Notified: July 27, 2016 Updated: August 04, 2016
Affected
We have not received a statement from the vendor.
We are not aware of further vendor information regarding this vulnerability.
Notified: July 27, 2016 Updated: August 04, 2016
Affected
We have not received a statement from the vendor.
We are not aware of further vendor information regarding this vulnerability.
Notified: July 27, 2016 Updated: August 04, 2016
Affected
We have not received a statement from the vendor.
We are not aware of further vendor information regarding this vulnerability.
Notified: July 27, 2016 Updated: July 11, 2017
Statement Date: August 17, 2016
Not Affected
We have not received a statement from the vendor.
We are not aware of further vendor information regarding this vulnerability.
Microsoft has informed CERT/CC that they are unaffected.
If you have feedback, comments, or additional information about this vulnerability, please send us [email](<mailto:[email protected]?Subject=VU%23877625 Feedback>).
Group | Score | Vector |
---|---|---|
Base | 2.9 | AV:A/AC:M/Au:N/C:P/I:N/A:N |
Temporal | 2.3 | E:POC/RL:OF/RC:C |
Environmental | 1.7 | CDP:ND/TD:M/CR:ND/IR:ND/AR:ND |
Thanks to Bas Venis for reporting this vulnerability. We also would like to thank Itzik Kotler and Amit Klein for their presentation at Black Hat 2016, and Alex Chapman and Paul Stone for their presentation at DEF CON 24
This document was written by Trent Novelly.
CVE IDs: | CVE-2016-5134, CVE-2016-1801 |
---|---|
Date Public: | 2016-08-04 Date First Published: |
8.8 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
5 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
NONE
Availability Impact
NONE
AV:N/AC:L/Au:N/C:P/I:N/A:N
0.017 Low
EPSS
Percentile
87.4%