CVE-2019-15552 in libflate Crate
Summary
by MITRE
An issue was discovered in the libflate crate before 0.1.25 for Rust. MultiDecoder::read has a use-after-free, leading to arbitrary code execution.
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Analysis
by VulDB Data Team • 12/04/2023
The vulnerability identified as CVE-2019-15552 resides within the libflate crate, a popular Rust library for decompressing data using various compression algorithms including deflate, gzip, and zlib. This issue affects versions prior to 0.1.25 and represents a critical security flaw that could enable remote code execution through a use-after-free condition. The libflate crate is widely utilized in Rust applications for handling compressed data streams, making this vulnerability particularly concerning for the broader Rust ecosystem and applications that rely on safe memory management practices. The vulnerability specifically manifests in the MultiDecoder::read function, which is responsible for reading and decompressing data streams from multiple compression formats within a single decoder instance. When processing malformed or specially crafted compressed data, the function fails to properly manage memory references, leading to a scenario where freed memory locations are accessed after they have been deallocated. This use-after-free condition creates a memory safety vulnerability that can be exploited by attackers to execute arbitrary code on systems running affected applications. The flaw occurs because the decoder does not properly validate the state transitions of compressed data streams or maintain proper reference counting for internal data structures, allowing attackers to manipulate the decompression process to trigger memory corruption. According to CWE-416, this vulnerability maps directly to the use-after-free weakness category, where memory is accessed after it has been freed, potentially leading to undefined behavior and code execution. The operational impact extends beyond simple memory corruption as it enables attackers to leverage the vulnerability for privilege escalation, denial of service, or complete system compromise depending on the execution context of the affected application. The ATT&CK framework categorizes this type of vulnerability under T1059.001 for command and scripting interpreter, as the arbitrary code execution capability allows adversaries to run malicious commands or scripts. Applications using libflate for decompressing user-provided or network-transmitted data are particularly at risk, as attackers can craft malicious compressed payloads that trigger the vulnerable code path. The vulnerability is especially dangerous in server-side applications or services that process compressed data from untrusted sources, as it can be exploited through simple data injection attacks without requiring complex exploitation techniques. Organizations should immediately update to libflate version 0.1.25 or later, which includes proper memory management fixes and validation of data stream states. Additionally, input validation and sanitization measures should be implemented as defensive programming practices to mitigate potential exploitation attempts. The fix implemented in version 0.1.25 addresses the core memory management issue by ensuring proper reference counting and state validation during decompression operations, preventing the access to freed memory locations. Security teams should also consider implementing network segmentation and monitoring for unusual decompression patterns that might indicate exploitation attempts, as the vulnerability can be triggered through network-based attacks or file processing scenarios.