[Onapsis Security Advisory 2015-010] SAP Mobile Platform DataVault Keystream Recovery

Onapsis Security Advisory 2015-010: SAP Mobile Platform DataVault
Keystream Recovery


1. Impact on Business
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By exploiting this vulnerability an attacker with access to a vulnerable
mobile device would be able to decrypt credentials and other sensitive
information stored in it, potentially being able to connect to other
business systems.

Risk Level: High


2. Advisory Information
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    * Public Release Date: 2015-08-12
    * Subscriber Notification Date: 2015-08-12
    * Last Revised: 2015-08-12
    * Security Advisory ID: ONAPSIS-2015-010
    * Onapsis SVS ID: ONAPSIS-00149
    * CVE: Not Assigned
    * Researcher: Fernando Russ
    * Initial Base CVSS v2:  5.4 (AV:L/AC:M/Au:N/C:C/I:P/A:N)


3. Vulnerability Information
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    * Vendor:  SAP AG
    * Affected Components:
       * SAP Mobile Platform 3.0 SP05 ClientHub

    * Vulnerability Class: Missing Required Cryptographic Step (CWE-325)
    * Remotely Exploitable: No
    * Locally Exploitable: Yes
    * Authentication Required: No
    * Original Advisory:
https://www.onapsis.com/research/security-advisories/SAP-Mobile-Platform-DataVault-Keystream-Recovery


4. Affected Components Description
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The SAP Mobile Platform 3.0 SP5 has an API called DataVault, which is
used to securely store data on mobile devices. As described by SAP AG
"[...] The DataVault APIs provide a secure way to persist and encrypt
data on the device. The data vault uses AES-256 symmetric encryption of
all its contents. The AES key is computed as a hash of the passcode
provided and a =E2=80=98salt=E2=80=99 value that can be supplied by the
device
application developer, or automatically generated through the API [...]"


5. Vulnerability Details
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Due to an incorrect implementation of the cryptografic algorithms and
parameters, it is possible to recover the keystream for the encrypted
data. As a result, it is possible to recover part of the plaintext
corresponding to an encrypted piece of data thus reverting the
encryption process of some values inside the DataVault without needing
the original secret key.

Furthermore, due to the lack of cryptographic integrity mechanisms in
the SAP DataVault an attacker recovering this keystream has the
possibility of re-encrypting (or modifying in practical terms) with some
limitations, some values previously encrypted inside the DataVault.


6. Solution
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Implement SAP Security Note 2094830.


7. Report Timeline
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    * 11/07/2014: Onapsis provides vulnerability information to SAP AG.
    * 11/08/2014: SAP AG confirms having received the information.
    * 04/08/2015: SAP AG releases SAP security note fixing the vulnerability
    * 08/12/2015: Security Advisory is released.


About Onapsis Research Labs
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Onapsis Research Labs provides the industry analysis of key security
issues that impact business-critical systems and applications.
Delivering frequent and timely security and compliance advisories with
associated risk levels, Onapsis Research Labs combine in-depth knowledge
and experience to deliver technical and business-context with sound
security judgment to the broader information security community.