CVE-2024-49749 Overview
CVE-2024-49749 is an out-of-bounds write vulnerability in the DGifSlurp function within dgif_lib.c, a GIF decoding library used by Android. The flaw stems from an integer overflow that allows attackers to write outside allocated memory boundaries during GIF parsing. Successful exploitation enables remote code execution without requiring elevated privileges. The vulnerability affects Android versions 12 through 15 and was addressed in the January 2025 Android Security Bulletin.
Critical Impact
Remote code execution is achievable through a maliciously crafted GIF file processed by a vulnerable Android device, with no additional privileges required.
Affected Products
- Google Android 12.0 and 12.1
- Google Android 13.0 and 14.0
- Google Android 15.0
Discovery Timeline
- 2025-01-21 - CVE-2024-49749 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2024-49749
Vulnerability Analysis
The vulnerability resides in the DGifSlurp routine inside dgif_lib.c, part of the GIF image decoding library bundled with Android. DGifSlurp is responsible for reading an entire GIF image into memory, including all frames and extension blocks. During processing, the function performs arithmetic on attacker-controlled values from the GIF header and frame descriptors to compute buffer sizes.
An integer overflow in these size calculations causes the allocator to reserve a buffer smaller than the data the parser subsequently writes. The mismatch produces an out-of-bounds write on the heap, classified as [CWE-787]. Because GIF parsing executes automatically when applications render images, exploitation does not require additional execution privileges on the device.
Root Cause
The root cause is unchecked integer arithmetic when computing allocation sizes for image data structures inside DGifSlurp. When width, height, or color table values from the GIF stream are multiplied, the product wraps around the integer type maximum. The resulting small allocation is followed by a write loop sized against the original, unwrapped values, corrupting adjacent heap memory.
Attack Vector
An attacker delivers a crafted GIF file to the target device through any vector that triggers image decoding. Common delivery paths include MMS messages, messaging applications with image previews, email clients, browsers rendering web content, and applications that thumbnail attachments. The CVSS vector indicates user interaction is required, consistent with the user opening or previewing the malicious image.
The vulnerability is described in prose because no public proof-of-concept code is available. See the Android Security Bulletin January 2025 for vendor technical details.
Detection Methods for CVE-2024-49749
Indicators of Compromise
- Anomalous crashes in processes that decode GIF imagery, such as messaging, browser, or gallery applications, with stack traces referencing DGifSlurp or dgif_lib.
- Unexpected child process creation or native library loads following the rendering of a GIF attachment.
- GIF files exhibiting malformed logical screen descriptors or oversized frame dimensions inconsistent with displayed content.
Detection Strategies
- Inspect inbound GIF files at the gateway for header field values that, when multiplied, exceed 32-bit integer bounds.
- Correlate application crash telemetry with recent media file access events to identify exploitation attempts against DGifSlurp.
- Monitor mobile endpoint logs for tombstone entries originating from image decoding threads in affected Android versions.
Monitoring Recommendations
- Centralize mobile device crash reports and parse them for signatures referencing GIF decoding libraries.
- Track Android OS patch level across the fleet and flag devices below the January 2025 security patch level.
- Alert on inbound MMS and messaging attachments with the image/gif MIME type exceeding typical size thresholds for the environment.
How to Mitigate CVE-2024-49749
Immediate Actions Required
- Apply the January 2025 Android security patch level (2025-01-01 or later) to all Android 12, 12.1, 13, 14, and 15 devices.
- Identify devices that cannot receive the patch and restrict their handling of untrusted GIF content through mobile device management policies.
- Educate users to avoid opening GIF files from untrusted senders until patching completes.
Patch Information
Google addressed CVE-2024-49749 in the Android Security Bulletin January 2025. Device manufacturers distribute the corresponding fix through their own update channels. Verify the security patch level under device settings to confirm remediation.
Workarounds
- Disable automatic image preview and auto-retrieval of MMS attachments in messaging applications on unpatched devices.
- Block or quarantine image/gif attachments at email and messaging gateways for users on out-of-date Android builds.
- Restrict installation of applications that render untrusted remote GIF content until the device receives the vendor patch.
# Verify current Android security patch level
adb shell getprop ro.build.version.security_patch
# Expected output: 2025-01-01 or later
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
