CVE-2017-8366 in Ettercap
Summary
by MITRE
The strescape function in ec_strings.c in Ettercap 0.8.2 allows remote attackers to cause a denial of service (heap-based buffer overflow and application crash) or possibly have unspecified other impact via a crafted filter that is mishandled by etterfilter.
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Analysis
by VulDB Data Team • 09/22/2020
The vulnerability identified as CVE-2017-8366 represents a critical heap-based buffer overflow in the strescape function within ec_strings.c of Ettercap version 0.8.2. This flaw exists within the etterfilter component which is designed to process and manipulate network traffic filters. The vulnerability arises when the strescape function fails to properly validate input length during string escaping operations, creating conditions where maliciously crafted filter inputs can exceed allocated buffer boundaries. The affected software is commonly used in network monitoring and packet manipulation scenarios, making it a prime target for attackers seeking to disrupt network operations or potentially escalate privileges through controlled crashes.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious filter string that triggers the buffer overflow during the strescape function execution. This function is responsible for escaping special characters in strings to ensure proper filter processing, but lacks adequate bounds checking mechanisms. When the input string exceeds the predetermined buffer size, memory corruption occurs in the heap memory space, leading to unpredictable application behavior. The vulnerability can result in immediate application crashes or more subtle memory corruption that might allow for arbitrary code execution depending on memory layout and exploitation conditions. According to CWE classification, this represents a classic buffer overflow vulnerability categorized under CWE-121 heap-based buffer overflow, which is particularly dangerous due to the potential for memory corruption leading to privilege escalation or remote code execution.
The operational impact of CVE-2017-8366 extends beyond simple denial of service scenarios, as it can severely compromise network monitoring capabilities that depend on Ettercap's etterfilter functionality. Network administrators using Ettercap for traffic analysis, man-in-the-middle attacks, or network reconnaissance may find their tools becoming unreliable or completely non-functional when processing malicious filter inputs. The vulnerability affects systems where Ettercap is deployed for network traffic inspection, particularly in security research environments, penetration testing scenarios, and network monitoring setups. Attackers could leverage this vulnerability to disrupt network operations by causing application crashes, potentially leading to complete service outages or creating opportunities for more sophisticated attacks through controlled system instability.
Mitigation strategies for this vulnerability require immediate patching of Ettercap to version 0.8.3 or later, which contains the necessary fixes for the buffer overflow conditions. System administrators should also implement network segmentation and access controls to limit exposure of Ettercap instances to untrusted network traffic. Input validation measures should be enhanced to prevent malformed filter inputs from reaching the strescape function, and regular security assessments should be conducted to identify similar vulnerabilities in other network monitoring tools. The ATT&CK framework categorizes this vulnerability under T1059 command and scripting interpreter execution, as exploitation typically involves crafting malicious inputs that trigger the vulnerable code path. Additionally, network monitoring systems should be configured to detect unusual patterns in filter processing that might indicate attempted exploitation of this vulnerability, providing an additional layer of defense against potential attackers.