CVE-2017-7703 in Wireshark
Summary
by MITRE
In Wireshark 2.2.0 to 2.2.5 and 2.0.0 to 2.0.11, the IMAP dissector could crash, triggered by packet injection or a malformed capture file. This was addressed in epan/dissectors/packet-imap.c by calculating a line's end correctly.
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Analysis
by VulDB Data Team • 11/29/2022
The vulnerability identified as CVE-2017-7703 represents a critical buffer overflow condition within Wireshark's IMAP dissector component that affected versions ranging from 2.2.0 through 2.2.5 and 2.0.0 through 2.0.11. This flaw emerged from improper handling of line termination boundaries when processing IMAP protocol traffic, creating a scenario where maliciously crafted network packets or corrupted capture files could trigger unexpected program behavior. The vulnerability falls under the category of memory corruption issues that can lead to application crashes or potentially more severe consequences depending on the execution environment. According to CWE classification, this corresponds to CWE-121, which describes heap-based buffer overflow conditions, and CWE-125, which addresses out-of-bounds read vulnerabilities that can occur when buffer boundaries are not properly validated.
The technical implementation of this vulnerability stems from the packet-imap.c dissector module's failure to correctly calculate line endings when parsing IMAP protocol data structures. When Wireshark processes IMAP traffic, it relies on specific parsing algorithms to interpret command responses and data streams from mail servers. The flaw occurred because the dissector did not properly account for variations in line termination sequences or malformed data that could cause pointer arithmetic to exceed allocated memory boundaries. This incorrect boundary calculation allowed attackers to inject specially crafted packets or manipulate capture files in ways that would cause the dissector to attempt memory access beyond the intended buffer limits. The vulnerability specifically targeted the IMAP protocol implementation within Wireshark's dissectors framework, where protocol-specific parsers must handle various data formats and edge cases without causing program instability.
The operational impact of CVE-2017-7703 extends beyond simple application crashes to potentially enable more sophisticated attack vectors within network analysis environments. Network security professionals and forensic analysts who rely on Wireshark for protocol analysis and incident response activities face significant operational risks when this vulnerability exists in their toolset. An attacker could leverage this vulnerability to cause denial of service against network monitoring systems that utilize affected Wireshark versions, effectively disrupting network analysis capabilities during critical incidents. The vulnerability's exploitation requires either packet injection capabilities or access to a malformed capture file, making it suitable for both active network attacks and passive manipulation of stored network data. From an ATT&CK framework perspective, this vulnerability maps to T1059.007 for command and scripting interpreter usage and T1490 for exploitation of remote services, as it enables attackers to disrupt network monitoring operations through protocol analysis tool manipulation.
The remediation for CVE-2017-7703 involved implementing proper boundary calculations within the epan/dissectors/packet-imap.c source file to ensure that line ending detection correctly handled all valid IMAP protocol formats. This fix required developers to enhance the dissector's input validation mechanisms and implement more robust memory management practices when processing IMAP protocol data. The solution addressed the root cause by ensuring that all buffer operations within the IMAP dissector properly validated data boundaries before performing any memory access operations. Network administrators should prioritize updating affected Wireshark installations to versions that include this fix, as the vulnerability represents a significant risk to network monitoring infrastructure. The fix also demonstrates the importance of proper input validation in protocol dissectors, as these components must handle potentially malicious data from network traffic without causing system instability. Organizations using Wireshark for security monitoring, incident response, and network troubleshooting should verify their installations are updated to prevent exploitation of this vulnerability, which could be leveraged to compromise network visibility capabilities during critical security events.