CVE-2016-3645 in Endpoint Protection
Summary
by MITRE
Integer overflow in the TNEF unpacker in the AntiVirus Decomposer engine in Symantec Advanced Threat Protection (ATP); Symantec Data Center Security:Server (SDCS:S) 6.x through 6.6 MP1; Symantec Web Gateway; Symantec Endpoint Protection (SEP) before 12.1 RU6 MP5; Symantec Endpoint Protection (SEP) for Mac; Symantec Endpoint Protection (SEP) for Linux before 12.1 RU6 MP5; Symantec Protection Engine (SPE) before 7.0.5 HF01, 7.5.x before 7.5.3 HF03, 7.5.4 before HF01, and 7.8.0 before HF01; Symantec Protection for SharePoint Servers (SPSS) 6.0.3 through 6.0.5 before 6.0.5 HF 1.5 and 6.0.6 before HF 1.6; Symantec Mail Security for Microsoft Exchange (SMSMSE) before 7.0_3966002 HF1.1 and 7.5.x before 7.5_3966008 VHF1.2; Symantec Mail Security for Domino (SMSDOM) before 8.0.9 HF1.1 and 8.1.x before 8.1.3 HF1.2; CSAPI before 10.0.4 HF01; Symantec Message Gateway (SMG) before 10.6.1-4; Symantec Message Gateway for Service Providers (SMG-SP) 10.5 before patch 254 and 10.6 before patch 253; Norton AntiVirus, Norton Security, Norton Internet Security, and Norton 360 before NGC 22.7; Norton Security for Mac before 13.0.2; Norton Power Eraser (NPE) before 5.1; and Norton Bootable Removal Tool (NBRT) before 2016.1 allows remote attackers to have an unspecified impact via crafted TNEF data.
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Analysis
by VulDB Data Team • 01/06/2025
The vulnerability identified as CVE-2016-3645 represents a critical integer overflow condition within the TNEF unpacker component of Symantec's AntiVirus Decomposer engine. This flaw affects multiple Symantec security products including Advanced Threat Protection, Data Center Security Server, Web Gateway, Endpoint Protection for various platforms, Protection Engine, SharePoint Servers, Mail Security solutions, Message Gateway systems, and various Norton products. The integer overflow occurs during the processing of TNEF (Transport Neutral Encapsulation Format) data structures which are commonly used in Microsoft Exchange environments to encapsulate rich text and attachments within email messages.
The technical implementation of this vulnerability stems from improper validation of integer values when processing TNEF data structures. When the decomposer engine encounters crafted TNEF data, it fails to properly handle integer arithmetic operations that exceed the maximum representable value for the data type being used. This overflow condition can lead to unpredictable behavior in memory allocation, buffer handling, and data processing routines. The vulnerability specifically impacts the TNEF unpacker functionality which is responsible for extracting and processing email attachments and rich text content from TNEF-encoded messages.
The operational impact of this vulnerability is severe and potentially exploitable by remote attackers. An attacker could craft malicious TNEF data that, when processed by any of the affected Symantec products, could trigger the integer overflow condition. This could result in memory corruption, application crashes, or potentially more dangerous outcomes such as arbitrary code execution depending on the specific implementation details and memory layout of the affected systems. The vulnerability's remote exploitability means that attackers do not need local access to compromise systems, making it particularly dangerous in networked environments where email processing is common.
Security professionals should implement immediate mitigations including applying the latest patches and updates provided by Symantec for all affected products. Organizations should also consider network-level restrictions on email traffic containing potentially malicious TNEF data, particularly from untrusted sources. The vulnerability aligns with CWE-190, Integer Overflow or Wraparound, and can be mapped to ATT&CK technique T1059.007 for execution through email-based attacks. Additionally, network segmentation and email filtering should be enhanced to prevent the delivery of potentially malicious TNEF content to critical systems. Organizations using legacy versions of Symantec products should prioritize upgrading to supported versions that contain the necessary security fixes to prevent exploitation of this integer overflow vulnerability.