Cisco ASA/Firepower Threat Defense Pseudo Random Number Generator Key entropy

Summaryinfo

A vulnerability marked as critical has been reported in Cisco ASA and Firepower Threat Defense. Affected by this issue is some unknown functionality of the component Pseudo Random Number Generator. Performing a manipulation results in entropy (Key). This vulnerability is known as CVE-2019-1715. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability, which was classified as critical, was found in Cisco ASA and Firepower Threat Defense (Firewall Software) (the affected version is unknown). This affects an unknown code of the component Pseudo Random Number Generator. The manipulation with an unknown input leads to a entropy vulnerability (Key). CWE is classifying the issue as CWE-332. The lack of entropy available for, or used by, a Pseudo-Random Number Generator (PRNG) can be a stability and security threat. This is going to have an impact on confidentiality. The summary by CVE is:

A vulnerability in the Deterministic Random Bit Generator (DRBG), also known as Pseudorandom Number Generator (PRNG), used in Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a cryptographic collision, enabling the attacker to discover the private key of an affected device. The vulnerability is due to insufficient entropy in the DRBG when generating cryptographic keys. An attacker could exploit this vulnerability by generating a large number of cryptographic keys on an affected device and looking for collisions with target devices. A successful exploit could allow the attacker to impersonate an affected target device or to decrypt traffic secured by an affected key that is sent to or from an affected target device.

The bug was discovered 05/01/2019. The weakness was published 05/03/2019 as cisco-sa-20190501-asa-ftd-entr as confirmed advisory (Website). It is possible to read the advisory at tools.cisco.com. This vulnerability is uniquely identified as CVE-2019-1715 since 12/06/2018. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 09/12/2023). The attack technique deployed by this issue is T1600.001 according to MITRE ATT&CK.

The vulnerability was handled as a non-public zero-day exploit for at least 2 days. During that time the estimated underground price was around $5k-$25k. The commercial vulnerability scanner Qualys is able to test this issue with plugin 316448 (Cisco Adaptive Security Appliance Software Low-Entropy Keys Vulnerability(cisco-sa-20190501-asa-ftd-entropy)).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Similar entries are available at VDB-134354 and VDB-134351. Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

• Firewall Software

Vendor

• Cisco

Name

• ASA
• Firepower Threat Defense

License

• commercial

Website

• Vendor: https://www.cisco.com/

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