What is dnsrslvr.dll?

dnsrslvr.dll is part of Microsoft® Windows® Operating System and developed by Microsoft Corporation according to the dnsrslvr.dll version information.

dnsrslvr.dll's description is "DNS Caching Resolver Service"

dnsrslvr.dll is digitally signed by Microsoft Windows.

dnsrslvr.dll is usually located in the 'C:\WINDOWS\System32\' folder.

None of the anti-virus scanners at VirusTotal reports anything malicious about dnsrslvr.dll.

If you have additional information about the file, please share it with the FreeFixer users by posting a comment at the bottom of this page.

Vendor and version information [?]

The following is the available information on dnsrslvr.dll:

PropertyValue
Product nameMicrosoft® Windows® Operating System
Company nameMicrosoft Corporation
File descriptionDNS Caching Resolver Service
Internal namednsrslvr.dll
Original filenamednsrslvr.dll.mui
Legal copyright© Microsoft Corporation. All rights reserved.
Product version10.0.18362.1
File version10.0.18362.1 (WinBuild.160101.0800)

Here's a screenshot of the file properties when displayed by Windows Explorer:

Product nameMicrosoft® Windows® Operating System
Company nameMicrosoft Corporation
File descriptionDNS Caching Resolver Service
Internal namednsrslvr.dll
Original filenamednsrslvr.dll.mui
Legal copyright© Microsoft Corporation. All rights..
Product version10.0.18362.1
File version10.0.18362.1 (WinBuild.160101.0800)

Digital signatures [?]

dnsrslvr.dll has a valid digital signature.

PropertyValue
Signer nameMicrosoft Windows
Certificate issuer nameMicrosoft Windows Production PCA 2011
Certificate serial number330000023241fb59996dcc4dff000000000232

VirusTotal report

None of the 69 anti-virus programs at VirusTotal detected the dnsrslvr.dll file.

None of the 69 anti-virus programs detected the dnsrslvr.dll file.

Sandbox Report

The following information was gathered by executing the file inside Cuckoo Sandbox.

Summary

Successfully executed process in sandbox.

Summary

{
    "dll_loaded": [
        "C:\\Users\\cuck\\AppData\\Local\\Temp\\99afa28e046c583d16df4f27be5769306f00d46e3fb0606624570b33d82018a6.bin.dll"
    ],
    "file_opened": [
        "C:\\Windows\\System32\\en-US\\KERNELBASE.dll.mui",
        "C:\\Users\\cuck\\AppData\\Local\\Temp\\99afa28e046c583d16df4f27be5769306f00d46e3fb0606624570b33d82018a6.bin.dll"
    ],
    "command_line": [
        "\"C:\\Windows\\System32\\rundll32.exe\" C:\\Users\\cuck\\AppData\\Local\\Temp\\99afa28e046c583d16df4f27be5769306f00d46e3fb0606624570b33d82018a6.bin.dll,DllMain"
    ],
    "file_exists": [
        "C:\\Users\\cuck\\AppData\\Local\\Temp\\99afa28e046c583d16df4f27be5769306f00d46e3fb0606624570b33d82018a6.bin.dll.manifest",
        "C:\\Users\\cuck\\AppData\\Local\\Temp\\99afa28e046c583d16df4f27be5769306f00d46e3fb0606624570b33d82018a6.bin.dll"
    ],
    "file_read": [
        "C:\\Users\\cuck\\AppData\\Local\\Temp\\99afa28e046c583d16df4f27be5769306f00d46e3fb0606624570b33d82018a6.bin.dll"
    ],
    "regkey_read": [
        "HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows\\Windows Error Reporting\\WMR\\Disable",
        "HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\GRE_Initialize\\DisableMetaFiles"
    ]
}

Generic

[
    {
        "process_path": "C:\\Windows\\System32\\rundll32.exe",
        "process_name": "rundll32.exe",
        "pid": 2588,
        "summary": {
            "file_opened": [
                "C:\\Windows\\System32\\en-US\\KERNELBASE.dll.mui"
            ],
            "file_exists": [
                "C:\\Users\\cuck\\AppData\\Local\\Temp\\99afa28e046c583d16df4f27be5769306f00d46e3fb0606624570b33d82018a6.bin.dll.manifest",
                "C:\\Users\\cuck\\AppData\\Local\\Temp\\99afa28e046c583d16df4f27be5769306f00d46e3fb0606624570b33d82018a6.bin.dll"
            ],
            "regkey_read": [
                "HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows\\Windows Error Reporting\\WMR\\Disable",
                "HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\GRE_Initialize\\DisableMetaFiles"
            ],
            "dll_loaded": [
                "C:\\Users\\cuck\\AppData\\Local\\Temp\\99afa28e046c583d16df4f27be5769306f00d46e3fb0606624570b33d82018a6.bin.dll"
            ]
        },
        "first_seen": 1570920785.875,
        "ppid": 2308
    },
    {
        "process_path": "C:\\Windows\\SysWOW64\\rundll32.exe",
        "process_name": "rundll32.exe",
        "pid": 2308,
        "summary": {
            "dll_loaded": [
                "C:\\Users\\cuck\\AppData\\Local\\Temp\\99afa28e046c583d16df4f27be5769306f00d46e3fb0606624570b33d82018a6.bin.dll"
            ],
            "file_opened": [
                "C:\\Users\\cuck\\AppData\\Local\\Temp\\99afa28e046c583d16df4f27be5769306f00d46e3fb0606624570b33d82018a6.bin.dll"
            ],
            "command_line": [
                "\"C:\\Windows\\System32\\rundll32.exe\" C:\\Users\\cuck\\AppData\\Local\\Temp\\99afa28e046c583d16df4f27be5769306f00d46e3fb0606624570b33d82018a6.bin.dll,DllMain"
            ],
            "file_exists": [
                "C:\\Users\\cuck\\AppData\\Local\\Temp\\99afa28e046c583d16df4f27be5769306f00d46e3fb0606624570b33d82018a6.bin.dll.manifest",
                "C:\\Users\\cuck\\AppData\\Local\\Temp\\99afa28e046c583d16df4f27be5769306f00d46e3fb0606624570b33d82018a6.bin.dll"
            ],
            "file_read": [
                "C:\\Users\\cuck\\AppData\\Local\\Temp\\99afa28e046c583d16df4f27be5769306f00d46e3fb0606624570b33d82018a6.bin.dll"
            ],
            "regkey_read": [
                "HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\GRE_Initialize\\DisableMetaFiles"
            ]
        },
        "first_seen": 1570920785.7031,
        "ppid": 2448
    },
    {
        "process_path": "C:\\Windows\\System32\\lsass.exe",
        "process_name": "lsass.exe",
        "pid": 476,
        "summary": {},
        "first_seen": 1570920785.3281,
        "ppid": 376
    }
]

Signatures

[
    {
        "markcount": 1,
        "families": [],
        "description": "This executable has a PDB path",
        "severity": 1,
        "marks": [
            {
                "category": "pdb_path",
                "ioc": "dnsrslvr.pdb",
                "type": "ioc",
                "description": null
            }
        ],
        "references": [],
        "name": "has_pdb"
    },
    {
        "markcount": 2,
        "families": [],
        "description": "The executable contains unknown PE section names indicative of a packer (could be a false positive)",
        "severity": 1,
        "marks": [
            {
                "category": "section",
                "ioc": ".wpp_sf",
                "type": "ioc",
                "description": null
            },
            {
                "category": "section",
                "ioc": ".didat",
                "type": "ioc",
                "description": null
            }
        ],
        "references": [],
        "name": "pe_features"
    },
    {
        "markcount": 1,
        "families": [],
        "description": "The file contains an unknown PE resource name possibly indicative of a packer",
        "severity": 1,
        "marks": [
            {
                "category": "resource name",
                "ioc": "MUI",
                "type": "ioc",
                "description": null
            }
        ],
        "references": [],
        "name": "pe_unknown_resource_name"
    }
]

Yara

The Yara rules did not detect anything in the file.

Network

{
    "tls": [],
    "udp": [
        {
            "src": "192.168.56.101",
            "dst": "192.168.56.255",
            "offset": 662,
            "time": 6.2171349525452,
            "dport": 137,
            "sport": 137
        },
        {
            "src": "192.168.56.101",
            "dst": "224.0.0.252",
            "offset": 5442,
            "time": 6.1562628746033,
            "dport": 5355,
            "sport": 51001
        },
        {
            "src": "192.168.56.101",
            "dst": "224.0.0.252",
            "offset": 5770,
            "time": 4.1620948314667,
            "dport": 5355,
            "sport": 53595
        },
        {
            "src": "192.168.56.101",
            "dst": "224.0.0.252",
            "offset": 6098,
            "time": 6.1652808189392,
            "dport": 5355,
            "sport": 53848
        },
        {
            "src": "192.168.56.101",
            "dst": "224.0.0.252",
            "offset": 6426,
            "time": 4.6644639968872,
            "dport": 5355,
            "sport": 54255
        },
        {
            "src": "192.168.56.101",
            "dst": "224.0.0.252",
            "offset": 6754,
            "time": 3.0563027858734,
            "dport": 5355,
            "sport": 55314
        },
        {
            "src": "192.168.56.101",
            "dst": "239.255.255.250",
            "offset": 7082,
            "time": 4.191125869751,
            "dport": 1900,
            "sport": 1900
        },
        {
            "src": "192.168.56.101",
            "dst": "239.255.255.250",
            "offset": 19016,
            "time": 4.1947619915009,
            "dport": 3702,
            "sport": 49152
        },
        {
            "src": "192.168.56.101",
            "dst": "239.255.255.250",
            "offset": 27400,
            "time": 6.265056848526,
            "dport": 1900,
            "sport": 53598
        }
    ],
    "dns_servers": [],
    "http": [],
    "icmp": [],
    "smtp": [],
    "tcp": [],
    "smtp_ex": [],
    "mitm": [],
    "hosts": [],
    "pcap_sha256": "d95df716e965fab185b31b62a924513dcec9efda1296b6969c38046b5e02ed66",
    "dns": [],
    "http_ex": [],
    "domains": [],
    "dead_hosts": [],
    "sorted_pcap_sha256": "89986516c1d0c39f6308b4d495a8147cdd4bd551e92ecbff3fec71bd862c342e",
    "irc": [],
    "https_ex": []
}

Screenshots

Screenshot from the sandboxScreenshot from the sandbox

TCP/UDP Listening Ports [?]

dnsrslvr.dll has been reported to listen on the following TCP/UDP ports.

PortProtocol# Occurrences
53174UDP v41

Hashes [?]

PropertyValue
MD522460a37fa73f13da804e501ba9dc769
SHA25699afa28e046c583d16df4f27be5769306f00d46e3fb0606624570b33d82018a6

What will you do with dnsrslvr.dll?

To help other users, please let us know what you will do with dnsrslvr.dll:



Malware or legitimate?

If you feel that you need more information to determine if your should keep this file or remove it, please read this guide.

Please select the option that best describe your thoughts on the information provided on this web page


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Comments

Please share with the other users what you think about this file. What does this file do? Is it legitimate or something that your computer is better without? Do you know how it was installed on your system? Did you install it yourself or did it come bundled with some other software? Is it running smoothly or do you get some error message? Any information that will help to document this file is welcome. Thank you for your contributions.

I'm reading all new comments so don't hesitate to post a question about the file. If I don't have the answer perhaps another user can help you.

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