Vulnerabilities > CVE-2017-3807 - Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability in Cisco Adaptive Security Appliance Software
Attack vector
NETWORK Attack complexity
LOW Privileges required
LOW Confidentiality impact
HIGH Integrity impact
HIGH Availability impact
HIGH Summary
A vulnerability in Common Internet Filesystem (CIFS) code in the Clientless SSL VPN functionality of Cisco ASA Software, Major Releases 9.0-9.6, could allow an authenticated, remote attacker to cause a heap overflow. The vulnerability is due to insufficient validation of user supplied input. An attacker could exploit this vulnerability by sending a crafted URL to the affected system. An exploit could allow the remote attacker to cause a reload of the affected system or potentially execute code. Note: Only traffic directed to the affected system can be used to exploit this vulnerability. This vulnerability affects systems configured in routed firewall mode only and in single or multiple context mode. This vulnerability can be triggered by IPv4 or IPv6 traffic. A valid TCP connection is needed to perform the attack. The attacker needs to have valid credentials to log in to the Clientless SSL VPN portal. Vulnerable Cisco ASA Software running on the following products may be affected by this vulnerability: Cisco ASA 5500 Series Adaptive Security Appliances, Cisco ASA 5500-X Series Next-Generation Firewalls, Cisco Adaptive Security Virtual Appliance (ASAv), Cisco ASA for Firepower 9300 Series, Cisco ASA for Firepower 4100 Series. Cisco Bug IDs: CSCvc23838.
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.
Exploit-Db
| description | Cisco ASA - WebVPN CIFS Handling Buffer Overflow. CVE-2017-3807. Dos exploit for Hardware platform. Tags: Denial of Service (DoS) |
| file | exploits/hardware/dos/41369.txt |
| id | EDB-ID:41369 |
| last seen | 2017-02-15 |
| modified | 2017-02-15 |
| platform | hardware |
| port | |
| published | 2017-02-15 |
| reporter | Exploit-DB |
| source | https://www.exploit-db.com/download/41369/ |
| title | Cisco ASA - WebVPN CIFS Handling Buffer Overflow |
| type | dos |
Nessus
| NASL family | CISCO |
| NASL id | CISCO-SA-20170208-ASA.NASL |
| description | According to its self-reported version and configuration, the Cisco Adaptive Security Appliance (ASA) software running on the remote device is affected by a heap overflow condition in the CIFS (Common Internet Filesystem) code within the Clientless SSL VPN functionality due to improper validation of user-supplied input. An authenticated, remote attacker can exploit this, via a specially crafted URL, to cause the device to reload or the execution of arbitrary code. Note that only traffic directed to the affected system can be used to exploit this issue, which affects systems configured in routed firewall mode only and in single or multiple context mode. A valid TCP connection is needed to perform the attack. Furthermore, the attacker would need to have valid credentials to log in to the Clientless SSL VPN portal. This vulnerability can be triggered by IPv4 or IPv6 traffic. |
| last seen | 2020-06-01 |
| modified | 2020-06-02 |
| plugin id | 97211 |
| published | 2017-02-16 |
| reporter | This script is Copyright (C) 2017-2020 and is owned by Tenable, Inc. or an Affiliate thereof. |
| source | https://www.tenable.com/plugins/nessus/97211 |
| title | Cisco ASA Clientless SSL VPN Functionality CIFS RCE (cisco-sa-20170208-asa) |
| code | |