CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
5.0	$0-$5k	0.00

Summaryinfo

A vulnerability was found in ISC BIND 9.8.1-P1. It has been declared as critical. This affects an unknown part of the component SRTT Algorithm Handler. Executing a manipulation can lead to privileges management. Additionally, an exploit exists. It is advised to implement the suggested workaround.

Detailsinfo

A vulnerability classified as critical was found in ISC BIND 9.8.1-P1 (Domain Name Software). This vulnerability affects some unknown processing of the component SRTT Algorithm Handler. The manipulation with an unknown input leads to a privileges management vulnerability. The CWE definition for the vulnerability is CWE-269. The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. As an impact it is known to affect confidentiality, and integrity.

The weakness was released 08/14/2013 by Roee Hay, Jonathan Kalechstein and Dr. Gabi Nakibly as Subverting BIND’s SRTT Algorithm: Derandomizing NS Selection as confirmed blog post (Website). The advisory is available at securityintelligence.com. The public release was coordinated with the vendor. The blog post contains:

Our attack abuses non-open resolvers, i.e. NSs that do not answer on queries that they are not authoritative of. Most of the resolvers around the Internet are non-open. The attacker does not need to control them, but simply needs to know their IP address. We will see how the attacker can take leverage of them in order lower the SRTT value of an arbitrary NS to an arbitrary value on some target resolver. The attacker also hosts a malicious NS. We assume that this malicious NS is the authority of some domain, i.e. malicious.foo. Let’s also assume that we want to lower the SRTT value of one of the authoritative NSs of ibm.com. It’s important to mention that our attack does not depend on the amount of authoritative NSs the target zone has, but for the sake of simplicity, in this example, the zone has two nameservers: NS1 and NS2. We will lower the SRTT of NS2 on the target resolver, so it will be queried before NS1.

The attack can be initiated remotely. Technical details are unknown but a public exploit is available. This vulnerability is assigned to T1068 by the MITRE ATT&CK project. The advisory points out:

An off-path DNS cache poisoning is an attack at which we assert that the adversary does not see the traffic between the DNS resolver and some name server (NS), but manages to poison the cache of the DNS resolver nevertheless. In order to do so, the attacker usually induces a request between the DNS resolver and the NS, and then races against the genuine DNS answer.

A public exploit has been developed by Roee Hay/Jonathan Kalechstein/Dr. Gabi Nakibly and been published immediately after the advisory. It is possible to download the exploit at securityintelligence.com. It is declared as proof-of-concept. The vulnerability was handled as a non-public zero-day exploit for at least 1 days. During that time the estimated underground price was around $25k-$100k. The advisory illustrates:

The attack begins by first querying the resolver for some domain the malicious NS is authoritative of, e.g. 666.malicious.foo. The resolver will eventually approach the malicious NS, which replies with a DNS delegation that contains: (1) A large list of non-open resolvers, (2) The NS that we try to lower the SRTT of, NS2. We assume that NS2 was already on the SRTT cache of the resolver and was contacted prior to the attack, so its SRTT is based on some real RTT value. Since the non-open resolvers were not on the cache, they will be added with very low values between 1 and 32 microseconds according to the SRTT algorithm. This means that they will be queried before NS2 by the NS selection. The resolver will query each of them and they will refuse since they are non-open resolvers. After each query the SRTT value of NS2 will be decayed, i.e. multiplied by 0.98. The resolver will time out after 30 seconds and we can force this timeout if the amount of non-open resolvers is sufficiently large. This means that the resolver will not even get to querying NS2 and at the end of the attack the SRTT of NS2 will be 0.98^n of ist original value, where n is the amount of non-open resolvers which were queried before the timeout.

The best possible mitigation is suggested to be Workaround. A possible mitigation has been published immediately after the disclosure of the vulnerability. The blog post contains the following remark:

The root cause of this vulnerability is that the resolver maintains a shared cache of SRTT values. The cache is shared in the sense that a malicious NS can affect SRTT values of NSs which are not related to it. We suggest to split the cache. For example, it can be split according to the currently queried zone.

The vulnerability is also documented in the vulnerability database at OSVDB (96276†). Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

• Domain Name Software

Vendor

• ISC

Name

• BIND

Version

• 9.8.1-P1

License

• open-source

Website

• Vendor: https://www.isc.org/

CPE 2.3info

• 🔍

CPE 2.2info

• 🔍

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.4
VulDB Meta Temp Score: 5.0

VulDB Base Score: 5.4
VulDB Temp Score: 5.0
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Privileges management
CWE: CWE-269 / CWE-266
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Proof-of-Concept
Author: Roee Hay/Jonathan Kalechstein/Dr. Gabi Nakibly
Download: 🔍
Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Workaround
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍
Exploit Delay Time: 🔍

Timelineinfo

08/12/2013 🔍
08/14/2013 +1 days 🔍
08/14/2013 +0 days 🔍
08/14/2013 +0 days 🔍
08/15/2013 +1 days 🔍
03/21/2019 +2044 days 🔍

Sourcesinfo

Vendor: isc.org

Advisory: Subverting BIND’s SRTT Algorithm: Derandomizing NS Selection
Researcher: Roee Hay, Jonathan Kalechstein, Dr. Gabi Nakibly
Status: Confirmed
Confirmation: 🔍
Coordinated: 🔍

GCVE (VulDB): GCVE-100-9946
OSVDB: 96276

scip Labs: https://www.scip.ch/en/?labs.20161013

Entryinfo

Created: 08/15/2013 12:20
Updated: 03/21/2019 10:32
Changes: 08/15/2013 12:20 (57), 03/21/2019 10:32 (2)
Complete: 🔍
Cache ID: 216:7C3:103

Discussion

Do you need the next level of professionalism?

Upgrade your account now!