Atlassian scrambles to fix zero-day security hole accidentally disclosed on Twitter

Updated Twitter security celeb SwiftOnSecurity on Tuesday inadvertently disclosed a zero-day vulnerability affecting enterprise software biz Atlassian, a flaw that may be echoed in IBM's Aspera software.

The SwiftOnSecurity Twitter account revealed that Atlassian provided a domain that resolved to a local server with a common SSL certificate for its Confluence cloud service, to enable the Atlassian Companion app to edit files in a preferred local application and save the files back to Confluence.

Confluence connects to its companion app through the browser using the rather unwieldy domain: https://atlassian-domain-for-localhost-connections-only.com.

The problem with this arrangement is that anyone with sufficient technical knowledge could copy the SSL key and use it to conduct a man-in-the-middle attack that could allow an attacker to redirect app traffic to a malicious site.

Google security engineer Tavis Ormandy confirmed that anyone using the app could be subjected to such an attack.

As Ormandy explained, "you can just grab the private key, and nothing is stopping you resolving this domain to something other than localhost. Therefore, no guarantee that you're talking to a trusted local service and not an attacker."

SwiftOnSecurity reported the issue to Atlassian and obtained CVE-2019-15006 for the bug.

In an email to The Register, Atlassian said it's aware of the issue and is actively working to resolve it. "We have requested that the certificate be revoked, and we're evaluating whether other technical solutions are required to protect our customers," a company spokesperson said.

In the Twitter discussion, Tim Stone, a moderator for StackApps, observed that IBM's Aspera plugin client uses a similar server scheme, local.connectme.us, for client-server communication.

According to Ormandy, that has the potential to be even worse. "There's a pre-generated CA certificate and a private key, if they add that to the system store, they're effectively disabling SSL," he wrote. "I would consider that *critical*."

There's no indication at the moment that IBM does add that certificate to its system store, according to Stone.

Nonetheless, Ormandy contends the certificate issue with local.connectme.us is real and argues the certificate should be revoked.

The Register asked IBM for comment but we've not heard back. ®

Updated to add

After the story was filed, an IBM spokesperson responded by noting that the tech giant issued a security bulletin for denial of service vulnerability affecting Aspera Connect 3.7 and 3.8 back in June. "We left the local.connectme.us in for backward compatibility while customers continue to upgrade their environments," the spinner explained.

Also, we note, the certificate for local.connectme.us has been revoked.