Summary
The bearertokenauth extension's server authenticator performs a simple, non-constant time string comparison of the received & configured bearer tokens.
Details
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token := auth[0] |
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expect := b.tokenString |
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if len(b.scheme) != 0 { |
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expect = fmt.Sprintf("%s %s", b.scheme, expect) |
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} |
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if expect != token { |
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return ctx, fmt.Errorf("scheme or token does not match: %s", token) |
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} |
For background on the type of vulnerability, see https://ropesec.com/articles/timing-attacks/.
Impact
This impacts anyone using the bearertokenauth server authenticator. Malicious clients with network access to the collector may perform a timing attack against a collector with this authenticator to guess the configured token, by iteratively sending tokens and comparing the response time. This would allow an attacker to introduce fabricated or bad data into the collector's telemetry pipeline.
Fix
The observable timing vulnerability was fixed by @axw in v0.107.0 (PR #34516) by using constant-time comparison.
Workarounds
- upgrade to v0.107.0 or above, or, if you're unable to upgrade at this time,
- don't expose the receiver using
bearertokenauth to network segments accessible by potential attackers, or
- change the receiver to use a different authentication extension instead, or
- disable the receiver relying on
bearertokenauth
axw Reporter
arminru Coordinator
frzifus Remediation reviewer
mx-psi Remediation reviewer
evan-bradley Remediation reviewer
Summary
The bearertokenauth extension's server authenticator performs a simple, non-constant time string comparison of the received & configured bearer tokens.
Details
opentelemetry-collector-contrib/extension/bearertokenauthextension/bearertokenauth.go
Lines 189 to 196 in 9128a92
For background on the type of vulnerability, see https://ropesec.com/articles/timing-attacks/.
Impact
This impacts anyone using the
bearertokenauthserver authenticator. Malicious clients with network access to the collector may perform a timing attack against a collector with this authenticator to guess the configured token, by iteratively sending tokens and comparing the response time. This would allow an attacker to introduce fabricated or bad data into the collector's telemetry pipeline.Fix
The observable timing vulnerability was fixed by @axw in v0.107.0 (PR #34516) by using constant-time comparison.
Workarounds
bearertokenauthto network segments accessible by potential attackers, orbearertokenauth