The Diffie-Hellman Key Agreement Protocol allows use of long exponents that arguably make certain calculations unnecessarily expensive, because the 1996 van Oorschot and Wiener paper found that "(appropriately) short exponents" can be used when there are adequate subgroup constraints, and these short exponents can lead to less expensive calculations than for long exponents. This issue is different from CVE-2002-20001 because it is based on an observation about exponent size, rather than an observation about numbers that are not public keys. The specific situations in which calculation expense would constitute a server-side vulnerability depend on the protocol (e.g., TLS, SSH, or IKE) and the DHE implementation details. In general, there might be an availability concern because of server-side resource consumption from DHE modular-exponentiation calculations. Finally, it is possible for an attacker to exploit this vulnerability and CVE-2002-20001 together.

The remote Ubuntu 22.04 LTS host has packages installed that are affected by a vulnerability as referenced in the USN-6854-1 advisory.

    It was discovered that OpenSSL failed to choose an appropriately short private key size when computing     shared-secrets in the Diffie-Hellman Key Agreement Protocol. A remote attacker could possibly use this     issue to cause OpenSSL to consume resources, resulting in a denial of service.

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLED15 / SLED_SAP15 / SLES15 / SLES_SAP15 / openSUSE 15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2023:2470-1 advisory.

  - The Diffie-Hellman Key Agreement Protocol allows use of long exponents that arguably make certain     calculations unnecessarily expensive, because the 1996 van Oorschot and Wiener paper found that     (appropriately) short exponents can be used when there are adequate subgroup constraints, and these     short exponents can lead to less expensive calculations than for long exponents. This issue is different     from CVE-2002-20001 because it is based on an observation about exponent size, rather than an observation     about numbers that are not public keys. The specific situations in which calculation expense would     constitute a server-side vulnerability depend on the protocol (e.g., TLS, SSH, or IKE) and the DHE     implementation details. In general, there might be an availability concern because of server-side resource     consumption from DHE modular-exponentiation calculations. Finally, it is possible for an attacker to     exploit this vulnerability and CVE-2002-20001 together. (CVE-2022-40735)

  - Issue summary: The AES-XTS cipher decryption implementation for 64 bit ARM platform contains a bug that     could cause it to read past the input buffer, leading to a crash. Impact summary: Applications that use     the AES-XTS algorithm on the 64 bit ARM platform can crash in rare circumstances. The AES-XTS algorithm is     usually used for disk encryption. The AES-XTS cipher decryption implementation for 64 bit ARM platform     will read past the end of the ciphertext buffer if the ciphertext size is 4 mod 5 in 16 byte blocks, e.g.
    144 bytes or 1024 bytes. If the memory after the ciphertext buffer is unmapped, this will trigger a crash     which results in a denial of service. If an attacker can control the size and location of the ciphertext     buffer being decrypted by an application using AES-XTS on 64 bit ARM, the application is affected. This is     fairly unlikely making this issue a Low severity one. (CVE-2023-1255)

  - Issue summary: Processing some specially crafted ASN.1 object identifiers or data containing them may be     very slow. Impact summary: Applications that use OBJ_obj2txt() directly, or use any of the OpenSSL     subsystems OCSP, PKCS7/SMIME, CMS, CMP/CRMF or TS with no message size limit may experience notable to     very long delays when processing those messages, which may lead to a Denial of Service. An OBJECT     IDENTIFIER is composed of a series of numbers - sub-identifiers - most of which have no size limit.
    OBJ_obj2txt() may be used to translate an ASN.1 OBJECT IDENTIFIER given in DER encoding form (using the     OpenSSL type ASN1_OBJECT) to its canonical numeric text form, which are the sub-identifiers of the OBJECT     IDENTIFIER in decimal form, separated by periods. When one of the sub-identifiers in the OBJECT IDENTIFIER     is very large (these are sizes that are seen as absurdly large, taking up tens or hundreds of KiBs), the     translation to a decimal number in text may take a very long time. The time complexity is O(n^2) with 'n'     being the size of the sub-identifiers in bytes (*). With OpenSSL 3.0, support to fetch cryptographic     algorithms using names / identifiers in string form was introduced. This includes using OBJECT IDENTIFIERs     in canonical numeric text form as identifiers for fetching algorithms. Such OBJECT IDENTIFIERs may be     received through the ASN.1 structure AlgorithmIdentifier, which is commonly used in multiple protocols to     specify what cryptographic algorithm should be used to sign or verify, encrypt or decrypt, or digest     passed data. Applications that call OBJ_obj2txt() directly with untrusted data are affected, with any     version of OpenSSL. If the use is for the mere purpose of display, the severity is considered low. In     OpenSSL 3.0 and newer, this affects the subsystems OCSP, PKCS7/SMIME, CMS, CMP/CRMF or TS. It also impacts     anything that processes X.509 certificates, including simple things like verifying its signature. The     impact on TLS is relatively low, because all versions of OpenSSL have a 100KiB limit on the peer's     certificate chain. Additionally, this only impacts clients, or servers that have explicitly enabled client     authentication. In OpenSSL 1.1.1 and 1.0.2, this only affects displaying diverse objects, such as X.509     certificates. This is assumed to not happen in such a way that it would cause a Denial of Service, so     these versions are considered not affected by this issue in such a way that it would be cause for concern,     and the severity is therefore considered low. (CVE-2023-2650)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The version of F5 Networks BIG-IP installed on the remote host is prior to 16.1.4 / 17.1.0. It is, therefore, affected by multiple vulnerabilities as referenced in the K83120834 advisory.

  - The Diffie-Hellman Key Agreement Protocol allows remote attackers (from the client side) to send arbitrary     numbers that are actually not public keys, and trigger expensive server-side DHE modular-exponentiation     calculations, aka a D(HE)at or D(HE)ater attack. The client needs very little CPU resources and network     bandwidth. The attack may be more disruptive in cases where a client can require a server to select its     largest supported key size. The basic attack scenario is that the client must claim that it can only     communicate with DHE, and the server must be configured to allow DHE. (CVE-2002-20001)

  - The Diffie-Hellman Key Agreement Protocol allows use of long exponents that arguably make certain     calculations unnecessarily expensive, because the 1996 van Oorschot and Wiener paper found that     (appropriately) short exponents can be used when there are adequate subgroup constraints, and these     short exponents can lead to less expensive calculations than for long exponents. This issue is different     from CVE-2002-20001 because it is based on an observation about exponent size, rather than an observation     about numbers that are not public keys. The specific situations in which calculation expense would     constitute a server-side vulnerability depend on the protocol (e.g., TLS, SSH, or IKE) and the DHE     implementation details. In general, there might be an availability concern because of server-side resource     consumption from DHE modular-exponentiation calculations. Finally, it is possible for an attacker to     exploit this vulnerability and CVE-2002-20001 together. (CVE-2022-40735)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Severity
201069	Ubuntu 22.04 LTS : OpenSSL vulnerability (USN-6854-1)	Nessus	Ubuntu Local Security Checks	high
177062	SUSE SLED15 / SLES15 / openSUSE 15 Security Update : openssl-3 (SUSE-SU-2023:2470-1)	Nessus	SuSE Local Security Checks	high
161373	F5 Networks BIG-IP : Diffie-Hellman key agreement protocol weaknesses (K83120834)	Nessus	F5 Networks Local Security Checks	high

Detections

Analytics

CVE-2022-40735

high

Tenable Plugins

high

high

high