Unauthenticated URL shortening via substring-only origin check
Published Jul 9, 2024 · Updated Aug 2, 2024
Authentication bypass in PrivateBin 1.5.0 through 1.7.3 allows remote attackers to shorten third-party URLs through a private YOURLS service. The YourlsProxy constructor uses strpos as a containment test for the configured basepath, so a crafted URL passes when that string occurs in its query or fragment rather than at offset zero. Exposure requires URL shortening, an authenticated private YOURLS service, a configured basepath, proxy, and token; generated links can conceal external phishing destinations, but existing pastes, configuration, and the token remain undisclosed.
Summary
What happened
Authentication bypass in PrivateBin 1.5.0 through 1.7.3 allows remote attackers to shorten third-party URLs through a private YOURLS service. The YourlsProxy constructor uses strpos as a containment test for the configured basepath, so a crafted URL passes when that string occurs in its query or fragment rather than at offset zero. Exposure requires URL shortening, an authenticated private YOURLS service, a configured basepath, proxy, and token; generated links can conceal external phishing destinations, but existing pastes, configuration, and the token remain undisclosed.
The record
- CVE
- CVE-2024-39899
- Published
- Jul 9, 2024
- Updated
- Aug 2, 2024
- Vendor
- PrivateBin
- Product
- PrivateBin
- Classifications
- CWE-20, CWE-791, CWE-305, T1608.005
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 9, 2024CVE publishedPublication date reported by the CVE source.
- Aug 2, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=>= 1.5.0, < 1.7.4
- Affected versionversion=1.5.0 <1.7.4
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Upstream YOURLS proxy filter-bypass requestproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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