You want to use the the SSIM Web Service APIs and would like to review documentation regarding this.
NOTE: The attached document is only supported for use with SSIM 4.8 Patch 2 or higher. The Symantec Security Information Manager (SSIM) Web Services host a set of application programming interface (API). These APIs enable the third-party WebService clients to connect and retrieve events at regular intervals from theInformation Manager server. These events are collected from the specific collectors that are configured for event collection and can be used for further processing. The SSIM Web Service APIs can be accessed over an HTTPS request only.
For more information please review the attached document.
Imported Document ID: TECH203947
Symantec Security Information Manager Web Service API User Guide.pdf