Cisco Secure Client: Incorrect Default Permissions
CVE-2023-20178 is a high-severity incorrect default permissions vulnerability in Cisco Secure Client from Cisco, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. Affected Cisco Secure Client versions: 4.9.00086; 4.9.01095; 4.9.02028, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 5.37% chance of exploitation within 30 days, which is in the top 7.22% of all scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Anyconnect Secure Mobility Client to 4.10.07061 or a later version.
- Update Secure Client to 5.0.02075 or a later version.
- Read the advisory on sec.cloudapps.cisco.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Cisco | Cisco Secure Client | 4.9.00086; 4.9.01095; 4.9.02028; 4.9.03047; 4.9.03049; 4.9.04043; 4.9.04053; 4.9.05042; and 16 more ranges | Not stated |
| Cisco | Anyconnect Secure Mobility Client | before 4.10.07061 | 4.10.07061 |
| Cisco | Secure Client | before 5.0.02075 | 5.0.02075 |
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
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- 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:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | CNA (cisco.com) |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
A vulnerability in the client update process of Cisco AnyConnect Secure Mobility Client Software for Windows and Cisco Secure Client Software for Windows could allow a low-privileged, authenticated, local attacker to elevate privileges to those of SYSTEM. The client update process is executed after a successful VPN connection is established. This vulnerability exists because improper permissions are assigned to a temporary directory that is created during the update process. An attacker could exploit this vulnerability by abusing a specific function of the Windows installer process. A successful exploit could allow the attacker to execute code with SYSTEM privileges.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Incorrect Default Permissions
During installation, installed file permissions are set to allow anyone to modify those files.
How developers prevent this class of flaw
- The architecture needs to access and modification attributes for files to only those users who actually require those actions.
- Compartmentalize the system to have safe areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
More Incorrect Default Permissions vulnerabilities (CWE-276)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in Cisco Secure Client
- 7.8 High severity
- 7.3 High severity
- 8.2 High severity
Recent Incorrect Default Permissions vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.7 High severity
- 7.8 High severity
- 7.8 High severity
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