Cisco Secure Web Appliance: Out-of-bounds Write
CVE-2023-20032 is a critical-severity out-of-bounds write vulnerability in Cisco Secure Web Appliance from Cisco, 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. Affected Cisco Secure Web Appliance versions: 11.7.0-406; 11.7.0-418; 11.7.1-049, 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 30.1% chance of exploitation within 30 days, which is in the top 1.76% of all scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Secure Endpoint to 1.20.2 or 1.21.1 or 7.5.9 or 8.1.5, whichever matches your release line, or a later version.
- Update Secure Endpoint Private Cloud to 3.6.0 or a later version.
- Update Web Security Appliance to 12.5.6 or 14.0.4-005 or 14.5.1-013 or 15.0.0-254, whichever matches your release line, or a later version.
- Read the advisory on sec.cloudapps.cisco.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 |
|---|---|---|---|
| Cisco | Cisco Secure Web Appliance | 11.7.0-406; 11.7.0-418; 11.7.1-049; 11.7.1-006; 11.7.1-020; 11.7.2-011; 11.8.0-414; 11.8.1-023; and 11 more ranges | Not stated |
| Cisco | Cisco Secure Endpoint | 6.1.9; 6.2.5; 6.3.7; 6.3.3; 7.0.5; 7.1.1; 1.12.1; 1.12.2; and 14 more ranges | Not stated |
| Cisco | Cisco Secure Endpoint Private Cloud Administration Portal | Not specified in the record | Not stated |
| Cisco | Secure Endpoint | before 1.20.2; before 1.21.1; before 7.5.9; 8.0.1.21160 up to, but not including, 8.1.5 | 1.20.2, 1.21.1, 7.5.9, 8.1.5 |
| Cisco | Secure Endpoint Private Cloud | before 3.6.0 | 3.6.0 |
| Cisco | Web Security Appliance | before 12.5.6; 14.0.0 up to, but not including, 14.0.4-005; 14.5.0 up to, but not including, 14.5.1-013; 15.0.0 up to, but not including, 15.0.0-254 | 12.5.6, 14.0.4-005, 14.5.1-013, 15.0.0-254 |
| Clamav | Clamav | 0.103.7 and earlier; 0.104.0 through 0.105.1; 1.0.0 | Not stated |
| Stormshield | Stormshield Network Security | 3.0.0 up to, but not including, 3.7.35; 3.8.0 up to, but not including, 3.11.23; 4.3.0 up to, but not including, 4.3.17; 4.4.0 up to, but not including, 4.6.4 | 3.7.35, 3.11.23, 4.3.17, 4.6.4 |
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 (cisco.com) |
| CVSS 3.1 | 9.8 | Critical | NVD |
Official description
On Feb 15, 2023, the following vulnerability in the ClamAV scanning library was disclosed: A vulnerability in the HFS+ partition file parser of ClamAV versions 1.0.0 and earlier, 0.105.1 and earlier, and 0.103.7 and earlier could allow an unauthenticated, remote attacker to execute arbitrary code. This vulnerability is due to a missing buffer size check that may result in a heap buffer overflow write. An attacker could exploit this vulnerability by submitting a crafted HFS+ partition file to be scanned by ClamAV on an affected device. A successful exploit could allow the attacker to execute arbitrary code with the privileges of the ClamAV scanning process, or else crash the process, resulting in a denial of service (DoS) condition. For a description of this vulnerability, see the ClamAV blog ["https://blog.clamav.net/"].
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Out-of-bounds Write
The product writes data past the end, or before the beginning, of the intended buffer.
How developers prevent this class of flaw
- Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
- Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in Cisco Secure Web Appliance
- 7.2 High severity
- 8.8 High severity
- 7.8 High severity
- 8.8 High severity
Recent Out-of-bounds Write vulnerabilities
- 9.8 Critical severity
- 9.8 Critical severity
- 8.1 High severity
- 7.8 High severity
- 7.8 High severity
- 8.6 High severity
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