IT Forensics · Linux
.Forensic analysis of .bashrc and profile files – examining shell initialisation as a source of persistence
Files such as .bashrc, .bash_profile or .profile are automatically executed at the start of every new shell session and are typically used to customise the working environment.
As their contents are executed automatically each time a session starts, they provide a simple yet effective persistence mechanism that is reactivated every time an affected user logs in.
Why LanCologne?
Since its foundation, LanCologne has specialised in professional IT forensics. Our staff have decades of experience in the field of information technology and assist companies, solicitors, private individuals and, on a regular basis, the courts in the technical investigation of complex digital matters.
The examination is, as a matter of principle, carried out exclusively on a forensic copy, a forensic image or a data source captured in a technically equivalent manner that preserves the integrity of the evidence. The original evidence remains unchanged and is stored in a manner that preserves its integrity.
Our services
We scan all relevant Shell profile files for all user accounts for any atypical or suspicious commands and categorise them according to potential persistence or data exfiltration mechanisms.
Typical areas of application
This is how an analysis of the shell profile files works
Once the backup has been completed, all relevant profile files for all user accounts are collected and their contents are checked. Unusual commands – particularly those relating to the network or designed to execute external scripts – are examined separately and their timing is determined using file system metadata.
Why is this analysis relevant from a forensic perspective?
A tampered .bashrc file can automatically execute malicious code every time a user logs in, without the user being immediately aware of it.
As these files can normally be edited by the user themselves, any tampering may be the result of either an external attack or a deliberate action on the part of the account holder; this is assessed on a case-by-case basis.
Frequently Asked Questions
LanCologne – Linux Forensics Cologne
Do you require a professional forensic investigation into „forensic analysis of .bashrc and profile files"? LanCologne can assist you with the legally admissible preservation of digital evidence and the transparent analysis of relevant Linux artefacts.
Related to this topic
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- Forensic analysis of PAM configuration – correctly classifying authentication modules
- Forensic analysis of Linux user accounts – reconstructing accounts, groups and permissions
- Forensic analysis of /etc/passwd and /etc/shadow – Examining central account databases in detail