Exponent strongSwan up to up to 4.x/5.6. IKEv2 Authentication gmp_rsa_public_key.c verify_emsa_pkcs1_signature digestAlgorithmparameters signature verification

CVSS Meta Temp Score
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CTI Interest Score
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6.4$0-$5k0.00

Summaryinfo

A vulnerability marked as critical has been reported in Exponent strongSwan up to up to 4.x/5.6.. This impacts the function verify_emsa_pkcs1_signature of the file gmp_rsa_public_key.c of the component IKEv2 Authentication. Performing a manipulation of the argument digestAlgorithmparameters as part of RSA Signature results in signature verification. This vulnerability is known as CVE-2018-16152. Remote exploitation of the attack is possible. No exploit is available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Exponent strongSwan up to up to 4.x/5.6. (Network Encryption Software). It has been classified as critical. This affects the function verify_emsa_pkcs1_signature of the file gmp_rsa_public_key.c of the component IKEv2 Authentication. The manipulation of the argument digestAlgorithmparameters as part of a RSA Signature leads to a signature verification vulnerability. CWE is classifying the issue as CWE-347. The product does not verify, or incorrectly verifies, the cryptographic signature for data. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

In verify_emsa_pkcs1_signature() in gmp_rsa_public_key.c in the gmp plugin in strongSwan 4.x and 5.x before 5.7.0, the RSA implementation based on GMP does not reject excess data in the digestAlgorithm.parameters field during PKCS#1 v1.5 signature verification. Consequently, a remote attacker can forge signatures when small public exponents are being used, which could lead to impersonation when only an RSA signature is used for IKEv2 authentication. This is a variant of CVE-2006-4790 and CVE-2014-1568.

The bug was discovered 09/24/2018. The weakness was published 09/26/2018 by Kevin Backhouse (Website). The advisory is shared at strongswan.org. This vulnerability is uniquely identified as CVE-2018-16152 since 08/29/2018. The exploitability is told to be difficult. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are known, but no exploit is available.

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 $0-$5k. The vulnerability scanner Nessus provides a plugin with the ID 117715 (Debian DLA-1522-1 : strongswan security update), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Debian Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 277550 (Fedora Security Update for strongswan (FEDORA-2018-9caa6528d2)).

Upgrading to version bis 4.x or 5.6.x eliminates this vulnerability. A possible mitigation has been published 2 hours after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at Tenable (117715) and SecurityFocus (BID 104263†). Similar entries are available at VDB-118481, VDB-119689 and VDB-124484. If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

Vendor

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.5
VulDB Meta Temp Score: 6.4

VulDB Base Score: 5.6
VulDB Temp Score: 5.4
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Signature verification
CWE: CWE-347 / CWE-345
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 117715
Nessus Name: Debian DLA-1522-1 : strongswan security update
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

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

Upgrade: strongSwan bis 4.x/5.6.x

Timelineinfo

05/23/2018 🔍
08/29/2018 +97 days 🔍
09/24/2018 +26 days 🔍
09/26/2018 +1 days 🔍
09/26/2018 +0 days 🔍
09/26/2018 +0 days 🔍
09/27/2018 +1 days 🔍
09/27/2018 +0 days 🔍
12/03/2025 +2624 days 🔍

Sourcesinfo

Advisory: USN-3771-1
Researcher: Kevin Backhouse
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2018-16152 (🔍)
GCVE (CVE): GCVE-0-2018-16152
GCVE (VulDB): GCVE-100-124485

OVAL: 🔍

SecurityFocus: 104263 - strongSwan CVE-2018-5388 Buffer Underflow Vulnerability

See also: 🔍

Entryinfo

Created: 09/27/2018 09:02
Updated: 12/03/2025 22:28
Changes: 09/27/2018 09:02 (80), 03/27/2020 09:38 (6), 05/19/2023 08:52 (4), 12/03/2025 22:28 (15)
Complete: 🔍
Cache ID: 216::103

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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