CVE-2022-35928 in AES Crypt
Summary
by MITRE • 08/04/2022
AES Crypt is a file encryption software for multiple platforms. AES Crypt for Linux built using the source on GitHub and having the version number 3.11 has a vulnerability with respect to reading user-provided passwords and confirmations via command-line prompts. Passwords lengths were not checked before being read. This vulnerability may lead to buffer overruns. This does _not_ affect source code found on aescrypt.com, nor is the vulnerability present when providing a password or a key via the `-p` or `-k` command-line options. The problem was fixed via in commit 68761851b and will be included in release 3.16. Users are advised to upgrade. Users unable to upgrade should us the `-p` or `-k` options to provide a password or key.
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Analysis
by VulDB Data Team • 08/30/2022
The CVE-2022-35928 vulnerability affects AES Crypt version 3.11 for Linux systems, representing a critical buffer overflow risk in the password handling mechanism. This flaw specifically manifests when the software processes user-provided passwords and confirmations through command-line prompts, creating a potential attack vector for malicious actors to exploit. The vulnerability stems from inadequate input validation where password lengths are not properly checked before being read into memory buffers, allowing for potentially excessive data to be processed and stored. Such oversight in the software's input processing creates a scenario where attackers could craft specially crafted password inputs that exceed the allocated buffer space, leading to memory corruption and potential system compromise. The vulnerability is particularly concerning because it operates at the command-line interface level where user interactions are common, making it accessible to both legitimate users and potential attackers who might attempt to exploit the buffer overflow for code execution or system disruption.
The technical implementation of this vulnerability aligns with CWE-121, which describes buffer overflow conditions where insufficient checks are performed on input data lengths before memory allocation. This weakness creates opportunities for attackers to manipulate the program's memory layout through carefully constructed inputs, potentially leading to arbitrary code execution or denial of service conditions. The vulnerability specifically affects the interactive password prompt functionality, where the software's failure to validate password length before processing creates an exploitable condition. The issue does not impact the software's functionality when passwords are provided via the `-p` or `-k` command-line options, indicating that the problem is isolated to the interactive input handling mechanism rather than the core encryption algorithms themselves. This distinction is important for security teams to understand as it helps focus mitigation efforts on the specific vulnerable code paths while preserving functionality for automated or scripted operations.
The operational impact of this vulnerability extends beyond simple buffer overflows to potentially enable more sophisticated attack vectors within the context of file encryption software. Attackers could leverage this weakness to disrupt the encryption process, potentially causing data corruption or system instability during file processing operations. The vulnerability's presence in the Linux version of AES Crypt specifically affects users who rely on interactive password prompts for encryption and decryption operations, which represents a significant portion of the user base that interacts with the software through command-line interfaces. Organizations using AES Crypt for data protection may face increased risk of system compromise if this vulnerability remains unpatched, particularly in environments where users might interact with the software through potentially untrusted interfaces or where automated scripts could be manipulated to exploit the buffer overflow condition.
Security practitioners should implement immediate mitigation strategies while planning for the necessary software upgrade to version 3.16 where the vulnerability has been resolved through commit 68761851b. The fix addresses the core issue by implementing proper input validation and length checking before password data is processed into memory buffers, thereby preventing the buffer overflow conditions that could be exploited by malicious actors. For users unable to upgrade immediately, the recommended workaround involves utilizing the `-p` or `-k` command-line options to provide passwords or keys directly, bypassing the vulnerable interactive prompt functionality entirely. This approach aligns with ATT&CK technique T1059.001 for command and scripting interpreter, where legitimate uses of command-line interfaces are leveraged to avoid vulnerable code paths while maintaining operational functionality. The vulnerability's remediation demonstrates the importance of proper input validation and buffer management in cryptographic software, where even seemingly minor implementation flaws can create significant security risks. Organizations should also consider implementing additional monitoring for unusual password input patterns that might indicate attempted exploitation of this vulnerability, particularly in environments where the software is used interactively.