TrustedSec has released a new red team framework called “Specula,” which enables Microsoft Outlook to be used as a command and control (C2) beacon for remote code execution. This framework leverages the CVE-2017-11774 vulnerability, a security flaw in Outlook that was patched in October 2017. By exploiting this vulnerability, Specula sets a custom home page in Outlook using WebView and Windows Registry values, even on systems running the latest Office 365 versions.
The attack involves creating a malicious Outlook home page via registry keys that point to an external web server controlled by the attacker. This setup allows the attacker to execute arbitrary commands through custom VBscript or JScript files, running within Outlook’s context. Although Microsoft had patched this issue and removed certain UI elements to mitigate the risk, attackers can still exploit it to persist and spread across compromised systems.
TrustedSec’s Specula framework demonstrates how attackers can use trusted applications like Outlook to evade detection and execute commands with elevated privileges. The ability to set a custom home page and execute scripts from it makes it a potent tool for cybercriminals looking to maintain persistence and control over infected devices.
This technique is notable for its effectiveness in bypassing existing security measures, as Outlook is a widely trusted process. The CVE-2017-11774 vulnerability has been linked to significant cyber espionage campaigns, including those by the Iranian-sponsored APT33 group. Despite past warnings and mitigations, Specula underscores the ongoing risks associated with such vulnerabilities.
