CVE-2022-39317: CWE-125: Out-of-bounds Read in FreeRDP FreeRDP
FreeRDP is a free remote desktop protocol library and clients. Affected versions of FreeRDP are missing a range check for input offset index in ZGFX decoder. A malicious server can trick a FreeRDP based client to read out of bound data and try to decode it. This issue has been addressed in version 2.9.0. There are no known workarounds for this issue.
AI Analysis
Technical Summary
CVE-2022-39317 is a medium-severity vulnerability affecting FreeRDP, an open-source implementation of the Remote Desktop Protocol (RDP) widely used for remote desktop access. The vulnerability is classified as a CWE-125: Out-of-bounds Read, specifically occurring in the ZGFX decoder component of FreeRDP versions prior to 2.9.0. The root cause is the absence of proper range checking on an input offset index during the decoding process. This flaw allows a malicious RDP server to send crafted data that causes the FreeRDP client to read memory outside the intended buffer boundaries. While this out-of-bounds read does not directly equate to code execution, it can lead to information disclosure or potentially cause client crashes due to memory corruption. The vulnerability requires the client to connect to a malicious or compromised RDP server, meaning exploitation is limited to scenarios where the client initiates a session with an attacker-controlled server. No authentication or user interaction beyond establishing the RDP connection is necessary. The issue was addressed in FreeRDP version 2.9.0 by implementing proper bounds checking in the ZGFX decoder. No known exploits have been reported in the wild, and no workarounds exist aside from upgrading to the patched version. Given FreeRDP's role as a foundational library used by multiple remote desktop clients across various platforms, this vulnerability has a broad potential impact on remote access environments that rely on FreeRDP for RDP connectivity.
Potential Impact
For European organizations, the impact of CVE-2022-39317 primarily concerns confidentiality and availability. Since the vulnerability allows an out-of-bounds read, attackers controlling an RDP server could potentially extract sensitive memory contents from the client, leading to information disclosure of credentials, session tokens, or other sensitive data in memory. Additionally, malformed data could cause client crashes, resulting in denial of service for remote desktop users. Organizations relying on FreeRDP-based clients for remote access, especially in critical infrastructure, government, finance, and healthcare sectors, could face operational disruptions or data leaks if users connect to malicious or compromised RDP servers. However, the requirement that the client connects to an attacker-controlled server limits the attack vector to scenarios such as remote employees connecting to untrusted RDP gateways or compromised internal servers. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits targeting this vulnerability. The broad use of FreeRDP in various Linux distributions and third-party remote desktop clients increases the scope of affected systems across European enterprises and public sector organizations.
Mitigation Recommendations
1. Immediate upgrade of all FreeRDP instances to version 2.9.0 or later to ensure the vulnerability is patched. 2. Audit and inventory all remote desktop clients and services to identify those using FreeRDP and verify their versions. 3. Restrict RDP client connections to trusted and verified servers only, employing network segmentation and firewall rules to limit exposure to potentially malicious RDP servers. 4. Implement network-level authentication and multi-factor authentication on RDP gateways to reduce the risk of connecting to rogue servers. 5. Monitor network traffic for unusual RDP connection patterns or attempts to connect to unknown or suspicious servers. 6. For environments where upgrading is delayed, consider isolating FreeRDP clients in controlled network zones or using alternative remote desktop clients not based on FreeRDP. 7. Educate users about the risks of connecting to untrusted remote desktop servers and enforce policies restricting such connections. 8. Employ endpoint detection and response (EDR) solutions to detect anomalous client crashes or memory access violations that could indicate exploitation attempts.
Affected Countries
Germany, France, United Kingdom, Netherlands, Italy, Spain, Poland, Sweden, Belgium, Austria
CVE-2022-39317: CWE-125: Out-of-bounds Read in FreeRDP FreeRDP
Description
FreeRDP is a free remote desktop protocol library and clients. Affected versions of FreeRDP are missing a range check for input offset index in ZGFX decoder. A malicious server can trick a FreeRDP based client to read out of bound data and try to decode it. This issue has been addressed in version 2.9.0. There are no known workarounds for this issue.
AI-Powered Analysis
Technical Analysis
CVE-2022-39317 is a medium-severity vulnerability affecting FreeRDP, an open-source implementation of the Remote Desktop Protocol (RDP) widely used for remote desktop access. The vulnerability is classified as a CWE-125: Out-of-bounds Read, specifically occurring in the ZGFX decoder component of FreeRDP versions prior to 2.9.0. The root cause is the absence of proper range checking on an input offset index during the decoding process. This flaw allows a malicious RDP server to send crafted data that causes the FreeRDP client to read memory outside the intended buffer boundaries. While this out-of-bounds read does not directly equate to code execution, it can lead to information disclosure or potentially cause client crashes due to memory corruption. The vulnerability requires the client to connect to a malicious or compromised RDP server, meaning exploitation is limited to scenarios where the client initiates a session with an attacker-controlled server. No authentication or user interaction beyond establishing the RDP connection is necessary. The issue was addressed in FreeRDP version 2.9.0 by implementing proper bounds checking in the ZGFX decoder. No known exploits have been reported in the wild, and no workarounds exist aside from upgrading to the patched version. Given FreeRDP's role as a foundational library used by multiple remote desktop clients across various platforms, this vulnerability has a broad potential impact on remote access environments that rely on FreeRDP for RDP connectivity.
Potential Impact
For European organizations, the impact of CVE-2022-39317 primarily concerns confidentiality and availability. Since the vulnerability allows an out-of-bounds read, attackers controlling an RDP server could potentially extract sensitive memory contents from the client, leading to information disclosure of credentials, session tokens, or other sensitive data in memory. Additionally, malformed data could cause client crashes, resulting in denial of service for remote desktop users. Organizations relying on FreeRDP-based clients for remote access, especially in critical infrastructure, government, finance, and healthcare sectors, could face operational disruptions or data leaks if users connect to malicious or compromised RDP servers. However, the requirement that the client connects to an attacker-controlled server limits the attack vector to scenarios such as remote employees connecting to untrusted RDP gateways or compromised internal servers. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits targeting this vulnerability. The broad use of FreeRDP in various Linux distributions and third-party remote desktop clients increases the scope of affected systems across European enterprises and public sector organizations.
Mitigation Recommendations
1. Immediate upgrade of all FreeRDP instances to version 2.9.0 or later to ensure the vulnerability is patched. 2. Audit and inventory all remote desktop clients and services to identify those using FreeRDP and verify their versions. 3. Restrict RDP client connections to trusted and verified servers only, employing network segmentation and firewall rules to limit exposure to potentially malicious RDP servers. 4. Implement network-level authentication and multi-factor authentication on RDP gateways to reduce the risk of connecting to rogue servers. 5. Monitor network traffic for unusual RDP connection patterns or attempts to connect to unknown or suspicious servers. 6. For environments where upgrading is delayed, consider isolating FreeRDP clients in controlled network zones or using alternative remote desktop clients not based on FreeRDP. 7. Educate users about the risks of connecting to untrusted remote desktop servers and enforce policies restricting such connections. 8. Employ endpoint detection and response (EDR) solutions to detect anomalous client crashes or memory access violations that could indicate exploitation attempts.
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Technical Details
- Data Version
- 5.1
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2022-09-02T00:00:00.000Z
- Cisa Enriched
- true
Threat ID: 682d9846c4522896dcbf4895
Added to database: 5/21/2025, 9:09:26 AM
Last enriched: 6/22/2025, 3:07:43 PM
Last updated: 8/6/2025, 4:09:26 PM
Views: 11
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