From 21281bd6e347fd50ee7c719621b884d15b403e70 Mon Sep 17 00:00:00 2001
From: Kenneth Rohde Christiansen
+ Targeted deanonymization attacks constitute a critical class of threats that jeopardize a users anonymity.
+ These attacks allow a malicious or partially compromised website (referred to as the “malicious site”) to
+ ascertain whether a website visitor possesses a specific public identifier, such as an email address or a
+ social media handle.
+
+ While anonymity may be a luxury for some, for certain individuals, it is far more than that—it is a matter
+ of survival. Consider for instance those who engage in political protests, work as journalists covering
+ sensitive topics, etc.
+
+ As an example, an attacker can privately share a resource with the target for instance using a public
+ resource sharing service (“victim site”), and then measure side-effects (indicating successful access)
+ on loading the resource via side-channels. If the logged in visitor can access the embedded resource
+ successfully, that indicates that the current visit is indeed the intended target.
+
+ Specifically, exposing reliable information about the total CPU pressure can let an attacking site
+ understand if a target of a cross-origin navigation (e.g. an iframe or pop-up window from another site)
+ performed a CPU-intensive operation.
+
+ Techniques such as pop-under and
+ tab-under can be used to hide the loading
+ from the user.
+
+ A practical attack is that the malicious website could open e.g., a popup to a resource on a victim site
+ to which the user is logged in (e.g. a video streaming site or online document editor) pointing to a
+ resource shared with specific users.
+
+ Assuming that loading the resource puts increased pressure on the CPU, this would create a side-channel
+ reveals to the attacking site if the user is logged into an account with access to the resource,
+ deanonymizing the user.
+
+ Given that modern CPUs recover quickly from high pressure, a mitigation strategy could be to temporarily
+ disable readings for a few seconds after loading popup and iframe content.
+
- Targeted deanonymization attacks constitute a critical class of threats that jeopardize a users anonymity.
+ Targeted de-anonymization attacks constitute a critical class of threats that jeopardize a user's anonymity.
These attacks allow a malicious or partially compromised website (referred to as the “malicious site”) to
ascertain whether a website visitor possesses a specific public identifier, such as an email address or a
social media handle.
@@ -1382,7 +1382,7 @@ Cross-site covert channel
a video conferencing session will typically exert sustained pressure on the CPU that makes it harder to
manipulate the pressure state in a predictive manner.
-
+ Targeted deanonymization attacks
+ Cross-site covert channel
a video conferencing session will typically exert sustained pressure on the CPU that makes it harder to
manipulate the pressure state in a predictive manner.
- Targeted deanonymization attacks
+ Targeted de-anonymization attacks
Targeted deanonymization attacks
from the user.
- A practical attack is that the malicious website could open e.g., a popup to a resource on a victim site + One possible attack is that the malicious website opens e.g., a popup to a resource on a victim site to which the user is logged in (e.g. a video streaming site or online document editor) pointing to a resource shared with specific users.
@@ -1392,8 +1392,8 @@- Given that modern CPUs recover quickly from high pressure, a mitigation strategy could be to temporarily - disable readings for a few seconds after loading popup and iframe content. + Given that modern CPUs recover quickly from high pressure, one possible mitigation strategy could be to + temporarily disable readings for a few seconds after loading popup and iframe content.