CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
SINGLE
Confidentiality Impact
PARTIAL
Integrity Impact
NONE
Availability Impact
NONE
AV:N/AC:L/Au:S/C:P/I:N/A:N
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
AI Score
Confidence
High
EPSS
Percentile
47.3%
CSV Injection, also known as Formula Injection, occurs when websites embed untrusted input inside CSV files. When a spreadsheet program opens a CSV, any cell starting with =
is interpreted by the software as a formula and could be abused by an attacker.
In Symfony 4.1, weβve added the opt-in csv_escape_formulas
option in CsvEncoder
, to prefix all cells starting by =
, +
, -
or @
by a tab \t
.
Since then, OWASP added 2 chars in that list: - Tab (0x09) - Carriage return (0x0D)
This makes our previous prefix char (Tab \t
) part of the vulnerable characters, and OWASP suggests using the single quote '
for prefixing the value.
Symfony now follows the OWASP recommendations and use the single quote '
to prefix formulas and adds the prefix to cells starting by \t
, \r
as well as =
, +
, -
and @
.
The patch for this issue is available here for branch 4.4.
We would like to thank Jake Barwell for reporting the issue and JΓ©rΓ©my DerussΓ© for fixing the issue.
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Published in #Security Advisories
CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
SINGLE
Confidentiality Impact
PARTIAL
Integrity Impact
NONE
Availability Impact
NONE
AV:N/AC:L/Au:S/C:P/I:N/A:N
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
AI Score
Confidence
High
EPSS
Percentile
47.3%