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T1558.005 Ccache Files

Adversaries may attempt to steal Kerberos tickets stored in credential cache files (or ccache). These files are used for short term storage of a user’s active session credentials. The ccache file is created upon user authentication and allows for access to multiple services without the user having to re-enter credentials.

The /etc/krb5.conf configuration file and the KRB5CCNAME environment variable are used to set the storage location for ccache entries. On Linux, credentials are typically stored in the /tmp directory with a naming format of krb5cc_%UID% or krb5.ccache. On macOS, ccache entries are stored by default in memory with an API:{uuid} naming scheme. Typically, users interact with ticket storage using kinit, which obtains a Ticket-Granting-Ticket (TGT) for the principal; klist, which lists obtained tickets currently held in the credentials cache; and other built-in binaries.21

Adversaries can collect tickets from ccache files stored on disk and authenticate as the current user without their password to perform Pass the Ticket attacks. Adversaries can also use these tickets to impersonate legitimate users with elevated privileges to perform Privilege Escalation. Tools like Kekeo can also be used by adversaries to convert ccache files to Windows format for further Lateral Movement. On macOS, adversaries may use open-source tools or the Kerberos framework to interact with ccache files and extract TGTs or Service Tickets via lower-level APIs.4653

Item Value
ID T1558.005
Sub-techniques T1558.001, T1558.002, T1558.003, T1558.004, T1558.005
Tactics TA0006
Platforms Linux, macOS
Version 1.0
Created 17 September 2024
Last Modified 15 April 2025

Procedure Examples

ID Name Description
S0357 Impacket Impacket tools – such as getST.py or ticketer.py – can be used to steal or forge Kerberos tickets using ccache files given a password, hash, aesKey, or TGT.28

Mitigations

ID Mitigation Description
M1047 Audit Enable and perform audits or scans of systems, permissions, insecure software, insecure configurations, etc. to identify potential weaknesses.5 For example, use auditd to audit access to hashes, machine tickets, or /tmp files. If using sssd and Vintela, ensure kerberos is disabled if not being used.7
M1043 Credential Access Protection Protect resources with Security Enhanced Linux (SELinux) by defining entry points, process types, and file labels.5

References

  1. ARC Labs, Dwyer, John. Gonzalez, Eric. Hudak, Tyler. (2024, October 1). Shining a Light in the Dark – How Binary Defense Uncovered an APT Lurking in Shadows of IT. Retrieved October 7, 2024. ↩

  2. Adepts of 0xCC. (2021, January 28). The Kerberos Credential Thievery Compendium (GNU/Linux). Retrieved September 17, 2024. ↩↩

  3. Benjamin Delpy. (n.d.). Kekeo. Retrieved October 4, 2021. ↩

  4. Cody Thomas. (2019, November 14). When Kirbi walks the Bifrost. Retrieved October 6, 2021. ↩

  5. Tim Wadhwa-Brown. (2018, November). Where 2 worlds collide Bringing Mimikatz et al to UNIX. Retrieved October 13, 2021. ↩↩↩

  6. Trevor Haskell. (2020, April 1). Kerberos Tickets on Linux Red Teams. Retrieved October 4, 2021. ↩

  7. Wadhwa-Brown, Tim. (2022). audit.rules. Retrieved September 17, 2024. ↩

  8. Boal, Calum. (2020, January 28). Abusing Kerberos From Linux - An Overview of Available Tools. Retrieved September 17, 2024. ↩