CVE-2020-3118

CVE Published	2020-02-05
Related CWE(s)	CWE-787: Out-of-bounds Write, CWE-134: Use of Externally-Controlled Format String
Related Vendor(s)	cisco
Related Product(s)	ios_xr
Exploitation Reported (CISA KEV)	2021-11-03
CVSS 3 Base Score	8.8 (HIGH)
CVSS 3 Attack Complexity	LOW
CVSS 3 Attack Vector	ADJACENT_NETWORK

A vulnerability in the Cisco Discovery Protocol implementation for Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to execute arbitrary code or cause a reload on an affected device. The vulnerability is due to improper validation of string input from certain fields in Cisco Discovery Protocol messages. An attacker could exploit this vulnerability by sending a malicious Cisco Discovery Protocol packet to an affected device. A successful exploit could allow the attacker to cause a stack overflow, which could allow the attacker to execute arbitrary code with administrative privileges on an affected device. Cisco Discovery Protocol is a Layer 2 protocol. To exploit this vulnerability, an attacker must be in the same broadcast domain as the affected device (Layer 2 adjacent).

Cyber Threat Graph Context

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Associated CAPEC Patterns

Format String Injection (CAPEC-135)

An adversary includes formatting characters in a string input field on the target application. Most applications assume that users will provide static text and may respond unpredictably to the presence of formatting character. For example, in certain functions of the C programming languages such as printf, the formatting character %s will print the contents of a memory location expecting this location to identify a string and the formatting character %n prints the number of DWORD written in the memory. An adversary can use this to read or write to memory locations or files, or simply to manipulate the value of the resulting text in unexpected ways. Reading or writing memory may result in program crashes and writing memory could result in the execution of arbitrary code if the adversary can write to the program stack.

String Format Overflow in syslog() (CAPEC-67)

This attack targets applications and software that uses the syslog() function insecurely. If an application does not explicitely use a format string parameter in a call to syslog(), user input can be placed in the format string parameter leading to a format string injection attack. Adversaries can then inject malicious format string commands into the function call leading to a buffer overflow. There are many reported software vulnerabilities with the root cause being a misuse of the syslog() function.

References

CVE-2020-3118

Cyber Threat Graph Context

Associated CAPEC Patterns

Format String Injection (CAPEC-135)

String Format Overflow in syslog() (CAPEC-67)

References

CVE.org

NIST National Vulnerability Database

CISA Known Exploited Vulnerabilities