Camera Firmware: Use of Externally-Controlled Format String
CVE-2023-5746 is a critical-severity use of externally-controlled format string vulnerability in Camera Firmware from Synology, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 1.0.5-0185 as the first without the flaw, so updating Camera Firmware to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 2.25% chance of exploitation within 30 days, higher than 83% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Camera Firmware to 1.0.5-0185 or a later version.
- Update Bc500 Firmware to 1.0.5-0185 or a later version.
- Update Tc500 Firmware to 1.0.5-0185 or a later version.
- Read the advisory on synology.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Synology | Camera Firmware | 1.0 up to, but not including, 1.0.5-0185; before 1.0.5-0185 | 1.0.5-0185 |
| Synology | Bc500 Firmware | before 1.0.5-0185 | 1.0.5-0185 |
| Synology | Tc500 Firmware | before 1.0.5-0185 | 1.0.5-0185 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 9.8 | Critical | CNA (synology.com) |
| CVSS 3.1 | 9.8 | Critical | NVD |
Official description
A vulnerability regarding use of externally-controlled format string is found in the cgi component. This allows remote attackers to execute arbitrary code via unspecified vectors. The following models with Synology Camera Firmware versions before 1.0.5-0185 may be affected: BC500 and TC500.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use of Externally-Controlled Format String
The product uses a function that accepts a format string as an argument, but the format string originates from an external source.
How developers prevent this class of flaw
- Choose a language that is not subject to this flaw.
- Ensure that all format string functions are passed a static string which cannot be controlled by the user, and that the proper number of arguments are always sent to that function as well. If at all possible, use functions that do not support the %n operator in format strings.
- Run compilers and linkers with high warning levels, since they may detect incorrect usage.
More Use of Externally-Controlled Format String vulnerabilities (CWE-134)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in Camera Firmware
- 9.8 Critical severity
- 7.5 High severity
- 7.2 High severity
- 9.8 Critical severity
- 7.2 High severity
Recent Use of Externally-Controlled Format String vulnerabilities
- 8.8 High severity
- 8.8 High severity
- 7.2 High severity
- 7.2 High severity
- 7.2 High severity
- 8.8 High severity
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