Query: intelligence brief on T1212
Matching passage: T1212 Exploitation for Credential Access. Tactics: credential access. Description: Adversaries may exploit software vulnerabilities in an attempt to collect credentials. Exploitation of a software vulnerability occurs when an adversary takes advantage of a programming error in a program, service, or within the operating system software or kernel itself to execute adversary-controlled code. Credentialing and authentication mechanisms may be targeted for exploitation by adversaries as a means to gain access to useful credentials or circumvent the process to gain authenticated access to systems. One example of this is `MS14-068`, which targets Kerberos and can be used to forge Kerberos tickets using domain user permissions.(Citation: Technet MS14-068)(Citation: ADSecurity Detecting Forged Tickets) Another example of this is replay attacks, in which the adversary intercepts data packets sent between parties and then later replays these packets. If services don't properly validate authentication requests, these replayed packets may allow an adversary to impersonate one of the parties and gain unauthorized access or privileges.(Citation: Bugcrowd Replay Attack)(Citation: Comparitech Replay Attack)(Citation: Microsoft Midnight Blizzard Replay Attack) Such exploitation has been demonstrated in cloud environments as well. For example, adversaries have exploited vulnerabilities in public cloud infrastructure that allowed for unintended authentication token creation and renewal.(Citation: Storm-0558 techniques for unauthorized email access) Exploitation for credential access may also result in Privilege Escalation depending on the process targeted or credentials obtained.
Near-miss passage: T1003.008 /etc/passwd and /etc/shadow. Tactics: credential access. Description: Adversaries may attempt to dump the contents of <code>/etc/passwd</code> and <code>/etc/shadow</code> to enable offline password cracking. Most modern Linux operating systems use a combination of <code>/etc/passwd</code> and <code>/etc/shadow</code> to store user account information, including password hashes in <code>/etc/shadow</code>. By default, <code>/etc/shadow</code> is only readable by the root user.(Citation: Linux Password and Shadow File Formats) Linux stores user information such as user ID, group ID, home directory path, and login shell in <code>/etc/passwd</code>. A "user" on the system may belong to a person or a service. All password hashes are stored in <code>/etc/shadow</code> - including entries for users with no passwords and users with locked or disabled accounts.(Citation: Linux Password and Shadow File Formats) Adversaries may attempt to read or dump the <code>/etc/passwd</code> and <code>/etc/shadow</code> files on Linux systems via command line utilities such as the <code>cat</code> command.(Citation: Arctic Wolf) Additionally, the Linux utility <code>unshadow</code> can be used to combine the two files in a format suited for password cracking utilities such as John the Ripper - for example, via the command <code>/usr/bin/unshadow /etc/passwd /etc/shadow > /tmp/crack.password.db</code>(Citation: nixCraft - John the Ripper). Since the user information stored in <code>/etc/passwd</code> are linked to the password hashes in <code>/etc/shadow</code>, an adversary would need to have access to both.