Cisco IOS, XR, and XE Software Buffer Overflow
CVE-2018-0167 is a high-severity improper restriction of operations within the bounds of a memory buffer vulnerability in Cisco IOS, IOS XE, and IOS XR, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. Affected Cisco IOS, IOS XE, and IOS XR versions: Cisco IOS, IOS XE, and IOS XR. The record does not name a fixed version, so check the vendor advisory. CISA added it to the Known Exploited Vulnerabilities catalogue on March 3, 2022, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update iOS Xr to 5.1.3 or a later version.
- CISA's required action: Apply updates per vendor instructions.
- Read the advisory on tools.cisco.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Cisco IOS, IOS XE, and IOS XR | Cisco IOS, IOS XE, and IOS XR | Cisco IOS, IOS XE, and IOS XR | Not stated |
| Cisco | iOS | 5.2.0.base; 15.6.3m1 and earlier; 15.2\(6\)e0a and earlier; 15.2\(4a\)ea5 and earlier | Not stated |
| Cisco | iOS Xe | 5.2.0.base; 15.6.3m1 and earlier; 15.2\(6\)e0a and earlier; 15.2\(4a\)ea5 and earlier | Not stated |
| Cisco | iOS Xr | 4.1 up to, but not including, 5.1.3 | 5.1.3 |
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
- AdjacentThe attacker must be on the same local network segment.
- 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:A/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 | 8.8 | High | NVD |
| CVSS 3.1 | 8.8 | High | CISA (ADP) |
| CVSS 2.0 | 8.3 | High | NVD |
Official description
Multiple Buffer Overflow vulnerabilities in the Link Layer Discovery Protocol (LLDP) subsystem of Cisco IOS Software, Cisco IOS XE Software, and Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition or execute arbitrary code with elevated privileges on an affected device. Cisco Bug IDs: CSCuo17183, CSCvd73487.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Restriction of Operations within the Bounds of a Memory Buffer
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary.
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.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- Deadline for US federal agencies to remediate, set by CISA.
- CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- ics-cert.us-cert.gov/advisories/ICSA-18-107-03Third Party Advisory, US Government Resource
- ics-cert.us-cert.gov/advisories/ICSA-18-107-04Third Party Advisory, US Government Resource
- ics-cert.us-cert.gov/advisories/ICSA-18-107-05Third Party Advisory, US Government Resource
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-0167US Government Resource
Other vulnerabilities in Cisco IOS, IOS XE, and IOS XR
- 8.0 High severity
Recent Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerabilities
- 9.8 Critical severity
- 9.8 Critical severity
- 7.8 High severity
Microsoft Office Memory Corruption Exploited
- 7.8 High severity
Microsoft Office Remote Code Execution Exploited
- 7.8 High severity
- 7.8 High severity
Linux Kernel PIE Stack Buffer Corruption Exploited
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