Ubuntu update for NSS



Risk Low
Patch available YES
Number of vulnerabilities 3
CVE-ID CVE-2018-0495
CVE-2018-12384
CVE-2018-12404
CWE-ID CWE-200
CWE-300
Exploitation vector Network
Public exploit Public exploit code for vulnerability #1 is available.
Public exploit code for vulnerability #3 is available.
Vulnerable software
 nss (Ubuntu package)
Operating systems & Components / Operating system package or component

Vendor Canonical Ltd.

Security Bulletin

This security bulletin contains information about 3 vulnerabilities.

1) Memory-cache side-channel attack

EUVDB-ID: #VU13370

Risk: Low

CVSSv4.0: 1.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P/U:Clear]

CVE-ID: CVE-2018-0495

CWE-ID: CWE-200 - Information exposure

Exploit availability: Yes

Description

The vulnerability allows a local attacker to obtain potentially sensitive information.

The vulnerability exists due to a leakage of information through memory caches when the affected library uses a private key to create Elliptic Curve Digital Signature Algorithm (ECDSA) signatures.  A local attacker can conduct a memory-cache side-channel attack on ECDSA signatures and recover sensitive information, such as ECDSA private keys, which could be used to conduct further attacks. 

Note: The vulnerability is known as the "Return Of the Hidden Number Problem" or ROHNP.

Mitigation

Update the affected packages.

Ubuntu 18.10
libnss3 - 2:3.36.1-1ubuntu1.1
Ubuntu 18.04 LTS
libnss3 - 2:3.35-2ubuntu2.1
Ubuntu 16.04 LTS
libnss3 - 2:3.28.4-0ubuntu0.16.04.4
Ubuntu 14.04 LTS
libnss3 - 2:3.28.4-0ubuntu0.14.04.4

Vulnerable software versions

nss (Ubuntu package): 2:3.28.4-0ubuntu0.14.04.1 - 2:3.28.4-0ubuntu0.16.04.2

CPE2.3 External links

https://usn.ubuntu.com/3850-1/


Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.

2) Man-in-the-middle attack

EUVDB-ID: #VU15735

Risk: Low

CVSSv4.0: 1.7 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2018-12384

CWE-ID: CWE-300 - Channel Accessible by Non-Endpoint ('Man-in-the-Middle')

Exploit availability: No

Description

The vulnerability allows a remote attacker to conduct man-in-the-middle attack on the target system.

The weakness exists due to ServerHello.random is all zero when handling a v2-compatible ClientHello. A remote attacker can use man-in-the-middle techniques to conduct passive replay attack and obtain potentially sensitive information.

Mitigation

Update the affected packages.

Ubuntu 18.10
libnss3 - 2:3.36.1-1ubuntu1.1
Ubuntu 18.04 LTS
libnss3 - 2:3.35-2ubuntu2.1
Ubuntu 16.04 LTS
libnss3 - 2:3.28.4-0ubuntu0.16.04.4
Ubuntu 14.04 LTS
libnss3 - 2:3.28.4-0ubuntu0.14.04.4

Vulnerable software versions

nss (Ubuntu package): 2:3.28.4-0ubuntu0.14.04.1 - 2:3.28.4-0ubuntu0.16.04.2

CPE2.3 External links

https://usn.ubuntu.com/3850-1/


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

3) Cache Attacks

EUVDB-ID: #VU16219

Risk: Medium

CVSSv4.0: 7 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N/E:P/U:Green]

CVE-ID: CVE-2018-12404

CWE-ID: CWE-300 - Channel Accessible by Non-Endpoint ('Man-in-the-Middle')

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a downgrade attack on the server and decrypt private keys on the target system.

The vulnerability exists due to a core weakness in TLS that relates to the handshaking of the session key which is used within the tunnel during parallelisation of thousands of oracle queries that occurs using a cluster of TLS servers which share the same public key certificate. A remote attacker can mount a microarchitectural side channel attack against a vulnerable implementation, obtain a network man-in-the-middle position, obtain the relevant data to sign and trigger the victim server to decrypt ciphertexts chosen by the adversary to perform a downgrade attack.






Mitigation

Update the affected packages.

Ubuntu 18.10
libnss3 - 2:3.36.1-1ubuntu1.1
Ubuntu 18.04 LTS
libnss3 - 2:3.35-2ubuntu2.1
Ubuntu 16.04 LTS
libnss3 - 2:3.28.4-0ubuntu0.16.04.4
Ubuntu 14.04 LTS
libnss3 - 2:3.28.4-0ubuntu0.14.04.4

Vulnerable software versions

nss (Ubuntu package): 2:3.28.4-0ubuntu0.14.04.1 - 2:3.28.4-0ubuntu0.16.04.2

CPE2.3 External links

https://usn.ubuntu.com/3850-1/


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.



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