ID CVE-2021-35394 Type cve Reporter cve@mitre.org Modified 2021-08-26T14:00:00
Description
Realtek Jungle SDK version v2.x up to v3.4.14B provides a diagnostic tool called 'MP Daemon' that is usually compiled as 'UDPServer' binary. The binary is affected by multiple memory corruption vulnerabilities and an arbitrary command injection vulnerability that can be exploited by remote unauthenticated attackers.
{"threatpost": [{"lastseen": "2021-08-24T02:09:46", "description": "Threat actors zeroing in on command injection vulnerabilities reported in Realtek chipsets just days after multiple flaws were discovered in the software developers kits (SDK) deployed across at least 65 separate vendors.\n\nOn Aug. 16 multiple [Realtek vulnerabilities](<https://www.iot-inspector.com/blog/advisory-multiple-issues-realtek-sdk-iot-supply-chain/>) were disclosed by IoT Inspector Research Lab. It took about 48 hours for attackers to start trying to exploit them. SAM Seamless Network reported two days after the bugs were made public, attackers made \u201cmultiple\u201d attempts breach the company\u2019s Secure Home product to [spread a new version of Mirai malware](<https://securingsam.com/realtek-vulnerabilities-weaponized/>).\n\n\u201cSpecifically, we noticed exploit attempts to \u2018formWsc\u2019 and \u2018formSysCmd\u2019 web pages,\u201d SAM\u2019s report on the incident said. \u201cThe exploit attempts to deploy a Mirai variant detected in March by Palo Alto Networks. Mirai is a notorious IoT and router malware circulating in various forms for the last 5 years. It was originally used to shut down large swaths of the internet but has since evolved into many variants for different purposes.\u201d \n[](<https://threatpost.com/infosec-insider-subscription-page/?utm_source=ART&utm_medium=ART&utm_campaign=InfosecInsiders_Newsletter_Promo/>)The report goes on to link another similar attack to the attack group. On Aug. 6 Juniper Networks found a vulnerability that just two days later was also exploited to try and deliver the same Mirai botnet using the same network subnet, the report explained.\n\n\u201cThis chain of events shows that hackers are actively looking for command injection vulnerabilities and use them to propagate widely used malware quickly,\u201d SAM said. \u201cThese kinds of vulnerabilities are easy to exploit and can be integrated quickly into existing hacking frameworks that attackers employ, well before devices are patched and security vendors can react.\u201d\n\nRealtek Semiconductor Corp. has not yet responded to Threatpost\u2019s request for comment, but the company did release [this advisory](<https://www.realtek.com/images/safe-report/Realtek_APRouter_SDK_Advisory-CVE-2021-35392_35395.pdf>) on CVE-2021-35392, CVE-2021-35393, CVE-2021-35394, CVE-2021-35395,\n\n[Mirai\u2019s source code has exploded in popularity](<https://threatpost.com/mirai-botnet-sees-big-2019-growth-shifts-focus-to-enterprises/146547/>) over the years, with more than [60 variants](<https://threatpost.com/mirai-variant-sonicwall-d-link-iot/164811/>) observed in the wild by last March. That number is still climbing with this latest iteration tailored to target the Realtek SDK flaws.\n\n## **Devices Targeted **\n\nConsidering the number of vendors impacted, researchers are concerned threat actors have ample first-move opportunities to exploit the bug before patches are deployed.\n\nSAM said the devices most exposed to the Realtek SDK bug are:\n\n * Netis E1+ extender\n * Edimax N150 and N300 Wi-Fo router\n * Repotec RP-WR5444 router\n\nThe original IoT Inspector report linked this kind of vulnerability to recent supply chain attacks on [SolarWinds](<https://threatpost.com/solarwinds-attackers-dhs-emails/165110/>) and [Kaseya](<https://threatpost.com/kaseya-patches-zero-day-exploits/167548/>).\n\n\u201cAs awareness for supply chain transparency is on the rise among security experts, this example is a pretty good showcase of the vast implications of an obscure IoT supply chain, The IoT Inspector report said.\n\nJust a day after the Realtek revelations, Mandiant in coordination with the Cybersecurity and Infrastructure Security Agency (CISA), reported [a flaw in IoT cloud](<https://threatpost.com/bug-iot-millions-devices-attackers-eavesdrop/168729/>) platform ThroughTek Kalay. The vulnerability would have potentially allowed an attacker to take over an IoT device to listen to live audio, watch real-time video and more.\n\n\u201cThese types of vulnerabilities are surfacing every day and there are probably many more that have yet to be discovered\u2026,\u201d SAM\u2019s Ran Hananel told Threatpost by email.\n\n## **Securing IoT **\n\nYaniv Bar-Dayan, co-founder of Vulcan Cyber told Threatpost that IoT security in inherently tricky because often it\u2019s not clear who is responsible for the data.\n\n\u201cWhile the responsibility to bring bug fixes and patches to market should lie on the shoulders of vendors, users should be sure to rely on tried-and-true security best practices in the meantime,\u201d Bar-Dayan said. \u201cEncrypt data, use sophisticated and unique passwords or multi-factor authentication, don\u2019t broadcast your network ID, double check configurations, and, above all else, patch early and often.\u201d\n\nBesides patching, Jake Williams at BreachQuest recommends limiting web interface access to the local network.\n\n\u201cThat won\u2019t stop attacks but does limit where they can be conducted from,\u201d Williams said. \u201cThis is particularly true for administrative interfaces.\u201d\n\nIt\u2019s also up to developers to know the code their using is secure. A [Software Bill of Materials (SBOMs)](<https://threatpost.com/executive-order-cybersecurity-federal-agencies/165056/>) are one solution being pushed by the U.S. government in the wake of the SolarWinds breach.\n\n\u201cDevelopers of any type of software like to use SDKs because it enables them to implement capabilities into their software without having to build it themselves,\u201d Hank Schless from Lookout told Threatpost. \u201cThis is broadly practiced, and there\u2019s a level of implicit trust that developers have in those that build these SDKs that everything packaged inside of them will be safe. However, just like with any other type of software, SDKs have their inevitable flaws.\u201d\n", "cvss3": {}, "published": "2021-08-23T14:08:42", "type": "threatpost", "title": "Attackers Actively Exploiting Realtek SDK Flaws", "bulletinFamily": "info", "cvss2": {}, "cvelist": ["CVE-2021-35392", "CVE-2021-35393", "CVE-2021-35394", "CVE-2021-35395"], "modified": "2021-08-23T14:08:42", "id": "THREATPOST:3CDCE42FF7DD2A68B77DC15C8BB1A6BA", "href": "https://threatpost.com/attackers-exploiting-realtek/168856/", "cvss": {"score": 0.0, "vector": "NONE"}}], "thn": [{"lastseen": "2021-08-24T05:35:04", "description": "[](<https://thehackernews.com/images/-PiZWCeBTtNg/YRtRHWkDPnI/AAAAAAAADjU/14jyow9NKv8ROnMPT_eVpKuR-OFvSGofACLcBGAsYHQ/s0/wifi.jpg>)\n\nTaiwanese chip designer Realtek is warning of [four security vulnerabilities](<https://www.realtek.com/images/safe-report/Realtek_APRouter_SDK_Advisory-CVE-2021-35392_35395.pdf>) in three software development kits (SDKs) accompanying its WiFi modules, which are used in almost 200 IoT devices made by at least 65 vendors.\n\nThe flaws, which affect Realtek SDK v2.x, Realtek \"Jungle\" SDK v3.0/v3.1/v3.2/v3.4.x/v3.4T/v3.4T-CT, and Realtek \"Luna\" SDK up to version 1.3.2, could be abused by attackers to fully compromise the target device and execute arbitrary code with the highest level of privilege \u2014\n\n * **CVE-2021-35392** (CVSS score: 8.1) - Heap buffer overflow vulnerability in 'WiFi Simple Config' server due to unsafe crafting of SSDP NOTIFY messages\n * **CVE-2021-35393** (CVSS score: 8.1) - Stack buffer overflow vulnerability in 'WiFi Simple Config' server due to unsafe parsing of the UPnP SUBSCRIBE/UNSUBSCRIBE Callback header\n * **CVE-2021-35394** (CVSS score: 9.8) - Multiple buffer overflow vulnerabilities and an arbitrary command injection vulnerability in 'UDPServer' MP tool\n * **CVE-2021-35395** (CVSS score: 9.8) - Multiple buffer overflow vulnerabilities in HTTP web server 'boa' due to unsafe copies of some overly long parameters\n\n[](<https://thehackernews.com/images/-EIgcKb_iBEk/YRtP5RJMxMI/AAAAAAAADjM/cTEyKOzn0asMcS1ihlaXo5YwzZ7xyMNxQCLcBGAsYHQ/s0/wifi-hack.gif>)\n\nImpacting devices that implement wireless capabilities, the list includes residential gateways, travel routers, WiFi repeaters, IP cameras to smart lightning gateways, or even connected toys from a wide range of manufacturers such as AIgital, ASUSTek, Beeline, Belkin, Buffalo, D-Link, Edimax, Huawei, LG, Logitec, MT-Link, Netis, Netgear, Occtel, PATECH, TCL, Sitecom, TCL, ZTE, Zyxel, and Realtek's own router lineup.\n\n[](<https://go.thn.li/privileged_728> \"Prevent Data Breaches\" )\n\n\"We got 198 unique fingerprints for devices that answered over UPnP. If we estimate that each device may have sold 5k copies (on average), the total count of affected devices would be close to a million,\" researchers said.\n\nWhile patches have been released for Realtek \"Luna\" SDK in version 1.3.2a, users of the \"Jungle\" SDK are recommended to backport the fixes provided by the company.\n\nThe security issues are said to have remained untouched in Realtek's codebase for more than a decade, German cybersecurity specialist IoT Inspector, which [discovered](<https://www.iot-inspector.com/blog/advisory-multiple-issues-realtek-sdk-iot-supply-chain/>) the weaknesses, said in a report published Monday three months after disclosing them to Realtek in May 2021.\n\n\"On the product vendor's end, [...] manufacturers with access to the Realtek source code [...] missed to sufficiently validate their supply chain, [and] left the issues unspotted and distributed the vulnerabilities to hundreds of thousands of end customers \u2014 leaving them vulnerable to attacks,\" the researchers said.\n\n**_Update:_** Three days after details about the Realtek vulnerabilities were revealed, active exploitation attempts have been detected to spread a variant of a Mirai malware and rope the compromised devices into the botnet. The same threat actor behind this Mirai-based botnet has also been linked to a [string of attacks](<https://thehackernews.com/2021/08/hackers-exploiting-new-auth-bypass-bug.html>) at least since February 2021, leveraging newly disclosed flaws in network security appliances and home routers to their advantage.\n\n\"This chain of events shows that hackers are actively looking for command injection vulnerabilities and use them to propagate widely used malware quickly,\" network security firm SAM Seamless Network [said](<https://securingsam.com/realtek-vulnerabilities-weaponized/>) last week. \"These kinds of vulnerabilities are easy to exploit and can be integrated quickly into existing hacking frameworks that attackers employ, well before devices are patched and security vendors can react.\"\n\n \n\n\nFound this article interesting? Follow THN on [Facebook](<https://www.facebook.com/thehackernews>), [Twitter _\uf099_](<https://twitter.com/thehackersnews>) and [LinkedIn](<https://www.linkedin.com/company/thehackernews/>) to read more exclusive content we post.\n", "cvss3": {}, "published": "2021-08-17T06:19:00", "type": "thn", "title": "Multiple Flaws Affecting Realtek Wi-Fi SDKs Impact Nearly a Million IoT Devices", "bulletinFamily": "info", "cvss2": {}, "cvelist": ["CVE-2021-35392", "CVE-2021-35393", "CVE-2021-35394", "CVE-2021-35395"], "modified": "2021-08-24T04:42:33", "id": "THN:B73C2EFCE2F6E4AC50F5CFFF3165A5C1", "href": "https://thehackernews.com/2021/08/multiple-flaws-affecting-realtek-wi-fi.html", "cvss": {"score": 0.0, "vector": "NONE"}}]}
