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MITRE ATT&CK® Technique

T1167: Securityd Memory

In OS X prior to El Capitan, users with root access can read plaintext keychain passwords of logged-in users because Apple’s keychain implementation allows these credentials to be cached so that users are not repeatedly prompted for passwords. [1] [2] Apple’s securityd utility takes the user’s logon password, encrypts it with PBKDF2, and stores this master key in memory. Apple also uses a set of keys and algorithms to encrypt the user’s password, but once the master key is found, an attacker need only iterate over the other values to unlock the final password. [1]

If an adversary can obtain root access (allowing them to read securityd’s memory), then they can scan through memory to find the correct sequence of keys in relatively few tries to decrypt the user’s logon keychain. This provides the adversary with all the plaintext passwords for users, WiFi, mail, browsers, certificates, secure notes, etc. [1] [3]

EnterpriseT1167TechniqueObject v1.1 Modified
Historical object

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Glexia's Take

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Official MITRE ATT&CK definition

Securityd Memory

In OS X prior to El Capitan, users with root access can read plaintext keychain passwords of logged-in users because Apple’s keychain implementation allows these credentials to be cached so that users are not repeatedly prompted for passwords. [1] [2] Apple’s securityd utility takes the user’s logon password, encrypts it with PBKDF2, and stores this master key in memory. Apple also uses a set of keys and algorithms to encrypt the user’s password, but once the master key is found, an attacker need only iterate over the other values to unlock the final password. [1]

If an adversary can obtain root access (allowing them to read securityd’s memory), then they can scan through memory to find the correct sequence of keys in relatively few tries to decrypt the user’s logon keychain. This provides the adversary with all the plaintext passwords for users, WiFi, mail, browsers, certificates, secure notes, etc. [1] [3]

View the same entry on attack.mitre.org (MITRE-hosted reference; in-page links above use the Glexia ATT&CK library.)

Glexia analysis

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ATT&CK relationship table

Related techniques

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1 rows
Domain ID Name Relationship / procedure
Enterprise T1555.002 Securityd Memory Sub-technique This object revoked by Securityd Memory.
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Change history

Object version and sync metadata

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ATT&CK release
19.1
Object version
1.1
Created
Modified
Raw hash
743c6ab0625cd9c2...
Imported snapshots across ATT&CK releases (1)
Release Bundle imported Object version Modified Status Raw hash
19.1 1.1 Current bundle Revoked 743c6ab0625c…
Raw source

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Source references

External references and citations

MITRE external references are preserved separately from Glexia analysis so citations remain traceable to their original source records.

  1. [1]
    OS X Keychain

    Juuso Salonen. (2012, September 5). Breaking into the OS X keychain. Retrieved July 15, 2017.

    Open source URL
  2. [2]
    External to DA, the OS X Way

    Alex Rymdeko-Harvey, Steve Borosh. (2016, May 14). External to DA, the OS X Way. Retrieved July 3, 2017.

    Open source URL
  3. [3]
    OSX Keydnap malware

    Marc-Etienne M.Leveille. (2016, July 6). New OSX/Keydnap malware is hungry for credentials. Retrieved July 3, 2017.

    Open source URL
  4. [4]
    mitre-attack T1167
    Open source URL
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