Adversaries may gather credentials from the proc filesystem or `/proc`. The proc filesystem is a pseudo-filesystem used as an interface to kernel data structures for Linux based systems managing virtual memory. For each process, the `/proc/<PID>/maps` file shows how memory is mapped within the process’s virtual address space. And `/proc/<PID>/mem`, exposed for debugging purposes, provides access to the process’s virtual address space.(Citation: Picus Labs Proc cump 2022)(Citation: baeldung Linux proc map 2022)

When executing with root privileges, adversaries can search these memory locations for all processes on a system that contain patterns indicative of credentials. Adversaries may use regex patterns, such as <code>grep -E "^[0-9a-f-]* r" /proc/"$pid"/maps | cut -d' ' -f 1</code>, to look for fixed strings in memory structures or cached hashes.(Citation: atomic-red proc file system) When running without privileged access, processes can still view their own virtual memory locations. Some services or programs may save credentials in clear text inside the process’s memory.(Citation: MimiPenguin GitHub May 2017)(Citation: Polop Linux PrivEsc Gitbook)

If running as or with the permissions of a web browser, a process can search the `/maps` & `/mem` locations for common website credential patterns (that can also be used to find adjacent memory within the same structure) in which hashes or cleartext credentials may be located.
Proc Filesystem
source_name: mitre-attack  url: https://attack.mitre.org/techniques/T1003/007  external_id: T1003.007     source_name: atomic-red proc file system  description: Atomic Red Team. (2023, November). T1003.007 - OS Credential Dumping: Proc Filesystem. Retrieved March 28, 2024.  url: https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1003.007/T1003.007.md     source_name: baeldung Linux proc map 2022  description: baeldung. (2022, April 8). Understanding the Linux /proc/id/maps File. Retrieved March 31, 2023.  url: https://www.baeldung.com/linux/proc-id-maps     source_name: Polop Linux PrivEsc Gitbook  description: Carlos Polop. (2023, March 5). Linux Privilege Escalation. Retrieved March 31, 2023.  url: https://book.hacktricks.xyz/linux-hardening/privilege-escalation#proc-usdpid-maps-and-proc-usdpid-mem     source_name: MimiPenguin GitHub May 2017  description: Gregal, H. (2017, May 12). MimiPenguin. Retrieved December 5, 2017.  url: https://github.com/huntergregal/mimipenguin     source_name: Picus Labs Proc cump 2022  description: Huseyin Can YUCEEL & Picus Labs. (2022, March 22). Retrieved March 31, 2023.  url: https://www.picussecurity.com/resource/the-mitre-attck-t1003-os-credential-dumping-technique-and-its-adversary-use     