9.1
CRITICAL
CVE-2024-5535
OpenSSL SSL_select_next_proto Buffer Overread
Description

Issue summary: Calling the OpenSSL API function SSL_select_next_proto with an empty supported client protocols buffer may cause a crash or memory contents to be sent to the peer. Impact summary: A buffer overread can have a range of potential consequences such as unexpected application beahviour or a crash. In particular this issue could result in up to 255 bytes of arbitrary private data from memory being sent to the peer leading to a loss of confidentiality. However, only applications that directly call the SSL_select_next_proto function with a 0 length list of supported client protocols are affected by this issue. This would normally never be a valid scenario and is typically not under attacker control but may occur by accident in the case of a configuration or programming error in the calling application. The OpenSSL API function SSL_select_next_proto is typically used by TLS applications that support ALPN (Application Layer Protocol Negotiation) or NPN (Next Protocol Negotiation). NPN is older, was never standardised and is deprecated in favour of ALPN. We believe that ALPN is significantly more widely deployed than NPN. The SSL_select_next_proto function accepts a list of protocols from the server and a list of protocols from the client and returns the first protocol that appears in the server list that also appears in the client list. In the case of no overlap between the two lists it returns the first item in the client list. In either case it will signal whether an overlap between the two lists was found. In the case where SSL_select_next_proto is called with a zero length client list it fails to notice this condition and returns the memory immediately following the client list pointer (and reports that there was no overlap in the lists). This function is typically called from a server side application callback for ALPN or a client side application callback for NPN. In the case of ALPN the list of protocols supplied by the client is guaranteed by libssl to never be zero in length. The list of server protocols comes from the application and should never normally be expected to be of zero length. In this case if the SSL_select_next_proto function has been called as expected (with the list supplied by the client passed in the client/client_len parameters), then the application will not be vulnerable to this issue. If the application has accidentally been configured with a zero length server list, and has accidentally passed that zero length server list in the client/client_len parameters, and has additionally failed to correctly handle a "no overlap" response (which would normally result in a handshake failure in ALPN) then it will be vulnerable to this problem. In the case of NPN, the protocol permits the client to opportunistically select a protocol when there is no overlap. OpenSSL returns the first client protocol in the no overlap case in support of this. The list of client protocols comes from the application and should never normally be expected to be of zero length. However if the SSL_select_next_proto function is accidentally called with a client_len of 0 then an invalid memory pointer will be returned instead. If the application uses this output as the opportunistic protocol then the loss of confidentiality will occur. This issue has been assessed as Low severity because applications are most likely to be vulnerable if they are using NPN instead of ALPN - but NPN is not widely used. It also requires an application configuration or programming error. Finally, this issue would not typically be under attacker control making active exploitation unlikely. The FIPS modules in 3.3, 3.2, 3.1 and 3.0 are not affected by this issue. Due to the low severity of this issue we are not issuing new releases of OpenSSL at this time. The fix will be included in the next releases when they become available.

INFO

Published Date :

June 27, 2024, 11:15 a.m.

Last Modified :

July 12, 2024, 2:15 p.m.

Remotely Exploitable :

Yes !

Impact Score :

5.2

Exploitability Score :

3.9
Public PoC/Exploit Available at Github

CVE-2024-5535 has a 3 public PoC/Exploit available at Github. Go to the Public Exploits tab to see the list.

Affected Products

The following products are affected by CVE-2024-5535 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Openssl openssl

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

None

Dockerfile Go

Updated: 1 week, 4 days ago
0 stars 0 fork 0 watcher
Born at : July 10, 2024, 3:05 p.m. This repo has been linked 4 different CVEs too.

None

Updated: 1 week, 5 days ago
0 stars 0 fork 0 watcher
Born at : July 5, 2024, 2:18 p.m. This repo has been linked 27 different CVEs too.

None

Updated: 12 hours, 10 minutes ago
4 stars 0 fork 0 watcher
Born at : Feb. 23, 2023, 5:42 a.m. This repo has been linked 452 different CVEs too.

Results are limited to the first 15 repositories due to potential performance issues.

The following table lists the changes that have been made to the CVE-2024-5535 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by [email protected]

    Jul. 12, 2024

    Action Type Old Value New Value
    Added Reference OpenSSL Software Foundation https://security.netapp.com/advisory/ntap-20240712-0005/ [No types assigned]
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Jul. 03, 2024

    Action Type Old Value New Value
    Added CVSS V3.1 CISA-ADP AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
  • CVE Modified by [email protected]

    Jun. 28, 2024

    Action Type Old Value New Value
    Added Reference OpenSSL Software Foundation http://www.openwall.com/lists/oss-security/2024/06/28/4 [No types assigned]
  • CVE Modified by [email protected]

    Jun. 27, 2024

    Action Type Old Value New Value
    Added Reference OpenSSL Software Foundation http://www.openwall.com/lists/oss-security/2024/06/27/1 [No types assigned]
  • CVE Received by [email protected]

    Jun. 27, 2024

    Action Type Old Value New Value
    Added Description Issue summary: Calling the OpenSSL API function SSL_select_next_proto with an empty supported client protocols buffer may cause a crash or memory contents to be sent to the peer. Impact summary: A buffer overread can have a range of potential consequences such as unexpected application beahviour or a crash. In particular this issue could result in up to 255 bytes of arbitrary private data from memory being sent to the peer leading to a loss of confidentiality. However, only applications that directly call the SSL_select_next_proto function with a 0 length list of supported client protocols are affected by this issue. This would normally never be a valid scenario and is typically not under attacker control but may occur by accident in the case of a configuration or programming error in the calling application. The OpenSSL API function SSL_select_next_proto is typically used by TLS applications that support ALPN (Application Layer Protocol Negotiation) or NPN (Next Protocol Negotiation). NPN is older, was never standardised and is deprecated in favour of ALPN. We believe that ALPN is significantly more widely deployed than NPN. The SSL_select_next_proto function accepts a list of protocols from the server and a list of protocols from the client and returns the first protocol that appears in the server list that also appears in the client list. In the case of no overlap between the two lists it returns the first item in the client list. In either case it will signal whether an overlap between the two lists was found. In the case where SSL_select_next_proto is called with a zero length client list it fails to notice this condition and returns the memory immediately following the client list pointer (and reports that there was no overlap in the lists). This function is typically called from a server side application callback for ALPN or a client side application callback for NPN. In the case of ALPN the list of protocols supplied by the client is guaranteed by libssl to never be zero in length. The list of server protocols comes from the application and should never normally be expected to be of zero length. In this case if the SSL_select_next_proto function has been called as expected (with the list supplied by the client passed in the client/client_len parameters), then the application will not be vulnerable to this issue. If the application has accidentally been configured with a zero length server list, and has accidentally passed that zero length server list in the client/client_len parameters, and has additionally failed to correctly handle a "no overlap" response (which would normally result in a handshake failure in ALPN) then it will be vulnerable to this problem. In the case of NPN, the protocol permits the client to opportunistically select a protocol when there is no overlap. OpenSSL returns the first client protocol in the no overlap case in support of this. The list of client protocols comes from the application and should never normally be expected to be of zero length. However if the SSL_select_next_proto function is accidentally called with a client_len of 0 then an invalid memory pointer will be returned instead. If the application uses this output as the opportunistic protocol then the loss of confidentiality will occur. This issue has been assessed as Low severity because applications are most likely to be vulnerable if they are using NPN instead of ALPN - but NPN is not widely used. It also requires an application configuration or programming error. Finally, this issue would not typically be under attacker control making active exploitation unlikely. The FIPS modules in 3.3, 3.2, 3.1 and 3.0 are not affected by this issue. Due to the low severity of this issue we are not issuing new releases of OpenSSL at this time. The fix will be included in the next releases when they become available.
    Added Reference OpenSSL Software Foundation https://www.openssl.org/news/secadv/20240627.txt [No types assigned]
    Added Reference OpenSSL Software Foundation https://github.com/openssl/openssl/commit/e86ac436f0bd54d4517745483e2315650fae7b2c [No types assigned]
    Added Reference OpenSSL Software Foundation https://github.com/openssl/openssl/commit/99fb785a5f85315b95288921a321a935ea29a51e [No types assigned]
    Added Reference OpenSSL Software Foundation https://github.com/openssl/openssl/commit/4ada436a1946cbb24db5ab4ca082b69c1bc10f37 [No types assigned]
    Added Reference OpenSSL Software Foundation https://github.com/openssl/openssl/commit/cf6f91f6121f4db167405db2f0de410a456f260c [No types assigned]
    Added Reference OpenSSL Software Foundation https://github.openssl.org/openssl/extended-releases/commit/b78ec0824da857223486660177d3b1f255c65d87 [No types assigned]
    Added Reference OpenSSL Software Foundation https://github.openssl.org/openssl/extended-releases/commit/9947251413065a05189a63c9b7a6c1d4e224c21c [No types assigned]
    Added CWE OpenSSL Software Foundation CWE-200
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2024-5535 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2024-5535 weaknesses.

CAPEC-13: Subverting Environment Variable Values Subverting Environment Variable Values CAPEC-22: Exploiting Trust in Client Exploiting Trust in Client CAPEC-59: Session Credential Falsification through Prediction Session Credential Falsification through Prediction CAPEC-60: Reusing Session IDs (aka Session Replay) Reusing Session IDs (aka Session Replay) CAPEC-79: Using Slashes in Alternate Encoding Using Slashes in Alternate Encoding CAPEC-116: Excavation Excavation CAPEC-169: Footprinting Footprinting CAPEC-224: Fingerprinting Fingerprinting CAPEC-285: ICMP Echo Request Ping ICMP Echo Request Ping CAPEC-287: TCP SYN Scan TCP SYN Scan CAPEC-290: Enumerate Mail Exchange (MX) Records Enumerate Mail Exchange (MX) Records CAPEC-291: DNS Zone Transfers DNS Zone Transfers CAPEC-292: Host Discovery Host Discovery CAPEC-293: Traceroute Route Enumeration Traceroute Route Enumeration CAPEC-294: ICMP Address Mask Request ICMP Address Mask Request CAPEC-295: Timestamp Request Timestamp Request CAPEC-296: ICMP Information Request ICMP Information Request CAPEC-297: TCP ACK Ping TCP ACK Ping CAPEC-298: UDP Ping UDP Ping CAPEC-299: TCP SYN Ping TCP SYN Ping CAPEC-300: Port Scanning Port Scanning CAPEC-301: TCP Connect Scan TCP Connect Scan CAPEC-302: TCP FIN Scan TCP FIN Scan CAPEC-303: TCP Xmas Scan TCP Xmas Scan CAPEC-304: TCP Null Scan TCP Null Scan CAPEC-305: TCP ACK Scan TCP ACK Scan CAPEC-306: TCP Window Scan TCP Window Scan CAPEC-307: TCP RPC Scan TCP RPC Scan CAPEC-308: UDP Scan UDP Scan CAPEC-309: Network Topology Mapping Network Topology Mapping CAPEC-310: Scanning for Vulnerable Software Scanning for Vulnerable Software CAPEC-312: Active OS Fingerprinting Active OS Fingerprinting CAPEC-313: Passive OS Fingerprinting Passive OS Fingerprinting CAPEC-317: IP ID Sequencing Probe IP ID Sequencing Probe CAPEC-318: IP 'ID' Echoed Byte-Order Probe IP 'ID' Echoed Byte-Order Probe CAPEC-319: IP (DF) 'Don't Fragment Bit' Echoing Probe IP (DF) 'Don't Fragment Bit' Echoing Probe CAPEC-320: TCP Timestamp Probe TCP Timestamp Probe CAPEC-321: TCP Sequence Number Probe TCP Sequence Number Probe CAPEC-322: TCP (ISN) Greatest Common Divisor Probe TCP (ISN) Greatest Common Divisor Probe CAPEC-323: TCP (ISN) Counter Rate Probe TCP (ISN) Counter Rate Probe CAPEC-324: TCP (ISN) Sequence Predictability Probe TCP (ISN) Sequence Predictability Probe CAPEC-325: TCP Congestion Control Flag (ECN) Probe TCP Congestion Control Flag (ECN) Probe CAPEC-326: TCP Initial Window Size Probe TCP Initial Window Size Probe CAPEC-327: TCP Options Probe TCP Options Probe CAPEC-328: TCP 'RST' Flag Checksum Probe TCP 'RST' Flag Checksum Probe CAPEC-329: ICMP Error Message Quoting Probe ICMP Error Message Quoting Probe CAPEC-330: ICMP Error Message Echoing Integrity Probe ICMP Error Message Echoing Integrity Probe CAPEC-472: Browser Fingerprinting Browser Fingerprinting CAPEC-497: File Discovery File Discovery CAPEC-508: Shoulder Surfing Shoulder Surfing CAPEC-573: Process Footprinting Process Footprinting CAPEC-574: Services Footprinting Services Footprinting CAPEC-575: Account Footprinting Account Footprinting CAPEC-576: Group Permission Footprinting Group Permission Footprinting CAPEC-577: Owner Footprinting Owner Footprinting CAPEC-616: Establish Rogue Location Establish Rogue Location CAPEC-643: Identify Shared Files/Directories on System Identify Shared Files/Directories on System CAPEC-646: Peripheral Footprinting Peripheral Footprinting CAPEC-651: Eavesdropping Eavesdropping
CVSS31 - Vulnerability Scoring System
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability