Unsecured Credentials: Credentials In Files
Adversaries may search local file systems and remote file shares for files containing insecurely stored credentials. These can be files created by users to store their own credentials, shared credential stores for a group of individuals, configuration files containing passwords for a system or service, or source code/binary files containing embedded passwords.
It is possible to extract passwords from backups or saved virtual machines through OS Credential Dumping.  Passwords may also be obtained from Group Policy Preferences stored on the Windows Domain Controller. 
In cloud environments, authenticated user credentials are often stored in local configuration and credential files. In some cases, these files can be copied and reused on another machine or the contents can be read and then used to authenticate without needing to copy any files. 
If an initial connectivity check fails, pngdowner attempts to extract proxy details and credentials from Windows Protected Storage and from the IE Credentials Store. This allows the adversary to use the proxy credentials for subsequent requests if they enable outbound HTTP access.
Preemptively search for files containing passwords and take actions to reduce the exposure risk when found.
Establish an organizational policy that prohibits password storage in files.
|Restrict File and Directory Permissions||
Restrict file shares to specific directories with access only to necessary users.
Ensure that developers and system administrators are aware of the risk associated with having plaintext passwords in software configuration files that may be left on endpoint systems or servers.
While detecting adversaries accessing these files may be difficult without knowing they exist in the first place, it may be possible to detect adversary use of credentials they have obtained. Monitor the command-line arguments of executing processes for suspicious words or regular expressions that may indicate searching for a password (for example: password, pwd, login, secure, or credentials). See Valid Accounts for more information.
- CG. (2014, May 20). Mimikatz Against Virtual Machine Memory Part 1. Retrieved November 12, 2014.
- Security Research and Defense. (2014, May 13). MS14-025: An Update for Group Policy Preferences. Retrieved January 28, 2015.
- Maddalena, C.. (2018, September 12). Head in the Clouds. Retrieved October 4, 2019.
- MaxXor. (n.d.). QuasarRAT. Retrieved July 10, 2018.
- Meltzer, M, et al. (2018, June 07). Patchwork APT Group Targets US Think Tanks. Retrieved July 16, 2018.
- Schroeder, W., Warner, J., Nelson, M. (n.d.). Github PowerShellEmpire. Retrieved April 28, 2016.
- Nettitude. (2018, July 23). Python Server for PoshC2. Retrieved April 23, 2019.
- Zanni, A. (n.d.). The LaZagne Project !!!. Retrieved December 14, 2018.
- Nicolas Verdier. (n.d.). Retrieved January 29, 2018.
- Belcher, P.. (2016, July 28). Tunnel of Gov: DNC Hack and the Russian XTunnel. Retrieved August 3, 2016.
- Yan, T., et al. (2018, November 21). New Wine in Old Bottle: New Azorult Variant Found in FindMyName Campaign using Fallout Exploit Kit. Retrieved November 29, 2018.
- Anthony, N., Pascual, C.. (2018, November 1). Trickbot Shows Off New Trick: Password Grabber Module. Retrieved November 16, 2018.
- Llimos, N., Pascual, C.. (2019, February 12). Trickbot Adds Remote Application Credential-Grabbing Capabilities to Its Repertoire. Retrieved March 12, 2019.
- F-Secure Labs. (2014). BlackEnergy & Quedagh: The convergence of crimeware and APT attacks. Retrieved March 24, 2016.
- Baumgartner, K. and Garnaeva, M.. (2014, November 3). BE2 custom plugins, router abuse, and target profiles. Retrieved March 24, 2016.
- Baker, B., Unterbrink H. (2018, July 03). Smoking Guns - Smoke Loader learned new tricks. Retrieved July 5, 2018.
- Crowdstrike Global Intelligence Team. (2014, June 9). CrowdStrike Intelligence Report: Putter Panda. Retrieved January 22, 2016.
- US-CERT. (2018, July 20). Alert (TA18-201A) Emotet Malware. Retrieved March 25, 2019.
- CIS. (2018, December 12). MS-ISAC Security Primer- Emotet. Retrieved March 25, 2019.
- Kamluk, V. & Gostev, A. (2016, February). Adwind - A Cross-Platform RAT. Retrieved April 23, 2019.
- Symantec DeepSight Adversary Intelligence Team. (2018, December 10). Seedworm: Group Compromises Government Agencies, Oil & Gas, NGOs, Telecoms, and IT Firms. Retrieved December 14, 2018.
- Symantec Security Response. (2016, September 6). Buckeye cyberespionage group shifts gaze from US to Hong Kong. Retrieved September 26, 2016.
- ASERT team. (2018, December 5). STOLEN PENCIL Campaign Targets Academia. Retrieved February 5, 2019.
- Proofpoint Staff. (2017, September 27). Threat Actor Profile: TA505, From Dridex to GlobeImposter. Retrieved May 28, 2019.
- Unit 42. (2017, December 15). Unit 42 Playbook Viewer. Retrieved December 20, 2017.
- Davis, S. and Caban, D. (2017, December 19). APT34 - New Targeted Attack in the Middle East. Retrieved December 20, 2017.
- Mandiant. (2018). Mandiant M-Trends 2018. Retrieved July 9, 2018.
- Bromiley, M., et al.. (2019, July 18). Hard Pass: Declining APT34’s Invite to Join Their Professional Network. Retrieved August 26, 2019.
- Security Response attack Investigation Team. (2019, March 27). Elfin: Relentless Espionage Group Targets Multiple Organizations in Saudi Arabia and U.S.. Retrieved April 10, 2019.
- Ackerman, G., et al. (2018, December 21). OVERRULED: Containing a Potentially Destructive Adversary. Retrieved January 17, 2019.
- Symantec Security Response. (2018, July 25). Leafminer: New Espionage Campaigns Targeting Middle Eastern Regions. Retrieved August 28, 2018.