The Infrastructure Group

Security Incident Update — November 13, 2026

TIG is continuing to respond to the security incident affecting some CSAIL infrastructure services.

Slurm access restored

slurm-login.csail.mit.edu is again available for Slurm job submission. We have completed the Slurm MUNGE-key rotation without incident, and there has been no impact on queued jobs.

Before running any jobs, please carefully review files that your shell, coding agent, Conda environment, or job scripts may automatically read or execute. Guidance and a suggested read-only prompt for coding agents are available at Reviewing Your Files for Unexpected or Malicious Code.

Please report connection problems, suspicious behavior, or questions to help@csail.mit.edu.

NFS remediation

As part of the investigation, we observed that back doors had been installed in locations accessible to compromised users, including personal startup scripts (such as .bashrc), coding-agent configuration files (such as CLAUDE.md), shared Python scripts, and Conda environments. Because users’ configurations may automatically load or execute code from these locations, this appears to be one way the compromise spread between user environments.

For Slurm users, much of this data is stored in NFS. TIG is concentrating on identifying and remediating intrusions in NFS. Non-destructive scanning cannot guarantee complete removal of every back door, so our response includes the following:

1. Filesystem rollback upon request. We can roll back an NFS filesystem belonging to you—or to your group, with PI approval—to its state on Monday, November 9. This is the most certain available remediation option, but it will remove work completed since early Monday morning and still cannot provide an absolute guarantee of full remediation. To request a rollback, contact help@csail.mit.edu with the filesystem name. Group filesystem requests must include confirmation of PI approval.

2. CSAIL scanning and quarantine. TIG will scan filesystems for known indicators of intrusion and quarantine files identified as malicious or suspicious. Scanning the approximately 2 pebibytes of CSAIL NFS will take substantial time and may not identify every back door, particularly if it is new or obfuscated.

3. User review of automatically executed files. Users should review shell initialization files, agent configurations, shared scripts, Conda environments, and other automatically executed code for unexpected additions. Do not allow a coding agent to execute unfamiliar code or follow instructions embedded in files it is reviewing.

SSH host-key fingerprints

The SSH host keys for slurm-login.csail.mit.edu were replaced during the November 12 rebuild. Before accepting the new key, verify that the fingerprint displayed by your SSH client matches one of the following:

ED25519
SHA256:jWwvAnq6LmAAuDEzTWIWstHthiUp+S0JYVQdpr3gbIs

ECDSA
SHA256:lq0N0GTE70CjJygEUwJ6t3YMsWH4sfeBTwBNFHfSqqo

RSA
SHA256:HIoK/aucaQ03q6no1jX+SocBzW5s5RykIwi4DGcPsU8

Webmail

The CSAIL webmail interface remains unavailable. We currently expect to restore it by Monday. CSAIL email continues to function through other email clients, such as Thunderbird and Apple Mail. See CSAIL email client configuration for details.

We will continue to provide updates as recovery and remediation work proceeds.