CVE-2015-0827 in Firefox
Summary
by MITRE
Heap-based buffer overflow in the mozilla::gfx::CopyRect function in Mozilla Firefox before 36.0, Firefox ESR 31.x before 31.5, and Thunderbird before 31.5 allows remote attackers to obtain sensitive information from uninitialized process memory via a malformed SVG graphic.
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Analysis
by VulDB Data Team • 03/10/2022
The vulnerability identified as CVE-2015-0827 represents a critical heap-based buffer overflow affecting Mozilla Firefox and Thunderbird applications. This flaw exists within the mozilla::gfx::CopyRect function which handles graphic rendering operations, specifically when processing malformed svg graphics. The vulnerability stems from insufficient input validation and memory management practices during the copying of rectangular graphic elements, creating conditions where attacker-controlled data can overwrite adjacent memory locations in the heap. The flaw is particularly dangerous because it allows remote attackers to execute information disclosure attacks by leveraging uninitialized memory contents that may contain sensitive data from other processes or application state information.
The technical implementation of this vulnerability involves the exploitation of memory corruption through improper bounds checking during graphic rendering operations. When Firefox processes malformed svg graphics, the CopyRect function fails to properly validate the dimensions and boundaries of rectangular data structures, leading to a situation where memory writes exceed allocated buffer limits. This heap overflow condition enables attackers to read uninitialized memory regions that may contain remnants of previous data, credentials, encryption keys, or other sensitive information from the process memory space. The vulnerability is classified under CWE-121 as a heap-based buffer overflow, which is a common class of memory safety issues that has been extensively documented in security literature and represents one of the most prevalent attack vectors in web browser exploitation.
The operational impact of CVE-2015-0827 extends beyond simple information disclosure to potentially enable more sophisticated attacks when combined with other vulnerabilities or exploitation techniques. Attackers can leverage this vulnerability to gain insights into application memory layout, process state, or even extract cryptographic keys and credentials that may be stored in adjacent memory regions. The vulnerability affects multiple product versions including Firefox versions prior to 36.0 and Firefox ESR 31.x versions before 31.5, as well as Thunderbird versions before 31.5, indicating a widespread exposure across the Mozilla ecosystem. This vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1566 for credential access, as it provides a pathway for attackers to gather information that can be used in subsequent phases of an attack chain. The remote nature of this vulnerability means that attackers do not require local system access or user interaction beyond visiting a malicious website, making it particularly dangerous for widespread exploitation.
Mitigation strategies for CVE-2015-0827 primarily focus on immediate patch application and software updates to versions that contain fixed implementations of the CopyRect function. Organizations should prioritize updating Firefox and Thunderbird installations to the patched versions that address the heap overflow conditions through improved memory management and bounds checking. Additionally, implementing network-level protections such as content security policies and sandboxing mechanisms can help limit the potential impact of exploitation attempts. Security teams should also consider monitoring for suspicious svg content in network traffic and implementing web application firewalls that can detect and block malformed graphic content. The vulnerability highlights the importance of regular security updates and proper memory safety practices in browser development, as it demonstrates how seemingly minor graphic rendering functions can create significant security risks when not properly validated against malicious inputs.