Vulnerabilities > CVE-2017-6720 - Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability in Cisco products
Summary
A vulnerability in the Secure Shell (SSH) subsystem of Cisco Small Business Managed Switches software could allow an authenticated, remote attacker to cause a reload of the affected switch, resulting in a denial of service (DoS) condition. The vulnerability is due to improper processing of SSH connections. An attacker could exploit this vulnerability by logging in to an affected switch via SSH and sending a malicious SSH message. This vulnerability affects the following Cisco products when SSH is enabled: Small Business 300 Series Managed Switches, Small Business 500 Series Stackable Managed Switches, 350 Series Managed Switches, 350X Series Stackable Managed Switches, 550X Series Stackable Managed Switches, ESW2 Series Advanced Switches. Cisco Bug IDs: CSCvb48377.
Vulnerable Configurations
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Buffer Overflow via Environment Variables This attack pattern involves causing a buffer overflow through manipulation of environment variables. Once the attacker finds that they can modify an environment variable, they may try to overflow associated buffers. This attack leverages implicit trust often placed in environment variables.
- Overflow Buffers Buffer Overflow attacks target improper or missing bounds checking on buffer operations, typically triggered by input injected by an attacker. As a consequence, an attacker is able to write past the boundaries of allocated buffer regions in memory, causing a program crash or potentially redirection of execution as per the attackers' choice.
- Client-side Injection-induced Buffer Overflow This type of attack exploits a buffer overflow vulnerability in targeted client software through injection of malicious content from a custom-built hostile service.
- Filter Failure through Buffer Overflow In this attack, the idea is to cause an active filter to fail by causing an oversized transaction. An attacker may try to feed overly long input strings to the program in an attempt to overwhelm the filter (by causing a buffer overflow) and hoping that the filter does not fail securely (i.e. the user input is let into the system unfiltered).
- MIME Conversion An attacker exploits a weakness in the MIME conversion routine to cause a buffer overflow and gain control over the mail server machine. The MIME system is designed to allow various different information formats to be interpreted and sent via e-mail. Attack points exist when data are converted to MIME compatible format and back.