Code execution via unbounded server-name parsing
Published Feb 26, 2021 · Updated Sep 17, 2024
Out-of-bounds write in synoagentregisterd in Synology DSM before 6.2.3-25426-3 allows man-in-the-middle attackers to execute code. The server-finder response parser uses sscanf with an unbounded %s conversion to copy a syno_finder_site value into a 128-byte stack buffer. Exploitation requires interception of the service's plaintext HTTP request to global.quickconnect.to; successful code execution begins in a root process constrained by AppArmor.
Summary
What happened
Out-of-bounds write in synoagentregisterd in Synology DSM before 6.2.3-25426-3 allows man-in-the-middle attackers to execute code. The server-finder response parser uses sscanf with an unbounded %s conversion to copy a syno_finder_site value into a 128-byte stack buffer. Exploitation requires interception of the service's plaintext HTTP request to global.quickconnect.to; successful code execution begins in a root process constrained by AppArmor.
The record
- CVE
- CVE-2021-26562
- Published
- Feb 26, 2021
- Updated
- Sep 17, 2024
- Vendor
- Synology
- Product
- Synology DiskStation Manager
- Classifications
- CWE-787, T1557
- Attack vector
- adjacent
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 26, 2021CVE publishedPublication date reported by the CVE source.
- Sep 17, 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=unspecified <6.2.3-25426-3
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.
Public exploit references
- Talos crafted server-finder response demonstrationproof 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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