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https://issues.apache.org/jira/browse/WW-5756?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Gouri Sankar A updated WW-5756:
-------------------------------
Description:
<s:a> builds its href attribute by neutralizing a literal quote (the href=
attribute, via
ensureAttributeSafelyNotEscaped) or blocking a literal "<script" substring (the
value= attribute, via
DefaultUrlHelper.buildUrl -- a check that appears to date back to
S2-002/CVE-2008-6682, WW-2427, based
on an exact symptom match with that historical ticket). Neither stops the value
itself from naming an
executable scheme: javascript:alert(1) needs no quote or <script substring to
run once the link is
activated.
Reproduced on main (7.5.0-SNAPSHOT) and confirmed the same vulnerable code is
present unchanged in
6.11.0, 7.3.0 and 7.4.0. Tested with embedded Tomcat 10.1.34, stock
struts-default, one
@StrutsParameter-bound action property q (the documented tag-attribute pattern):
<s:a href="%\{q}"> q=javascript:alert(document.cookie) -> <a
href="javascript:alert(...)">
<s:a value="%\{q}"> q=javascript:alert(document.cookie) -> <a
href="javascript:alert(...)">
<s:a anchor="%\{q}"> q=javascript:alert(document.cookie) -> lands as a URL
fragment, inert (safe)
Also confirmed vulnerable before a fix: case variation (JaVaScRiPt:), an
embedded tab or newline inside
the scheme (a browser's own URL parser strips these before reading the scheme,
per the WHATWG URL spec,
so a naive startsWith("javascript:") filter would miss them), and a leading
space or NUL.
Proposed fix (patch available): a new allowlist-based check (http, https,
mailto, tel), applied before
the existing quote/<script checks, with the same WHATWG-style normalization so
the tab/newline-split
variant is still caught. I have a patch with regression tests ready and will
open a PR referencing this
ticket.
was:
<s:a> builds its href attribute by neutralizing a literal quote (the href=
attribute, via
ensureAttributeSafelyNotEscaped) or blocking a literal "<script" substring (the
value= attribute, via
DefaultUrlHelper.buildUrl -- a check that appears to date back to
S2-002/CVE-2008-6682, WW-2427, based
on an exact symptom match with that historical ticket). Neither stops the value
itself from naming an
executable scheme: javascript:alert(1) needs no quote or <script substring to
run once the link is
activated.
Reproduced on main (7.5.0-SNAPSHOT) and confirmed the same vulnerable code is
present unchanged in
6.11.0, 7.3.0 and 7.4.0. Tested with embedded Tomcat 10.1.34, stock
struts-default, one
@StrutsParameter-bound action property q (the documented tag-attribute pattern):
<s:a href="%\{q}"> q=javascript:alert(document.cookie) -> <a
href="javascript:alert(...)">
<s:a value="%\{q}"> same payload -> <a
href="javascript:alert(...)">
<s:a anchor="%\{q}"> same payload -> lands as a
URL fragment, inert (safe)
Also confirmed vulnerable before a fix: case variation (JaVaScRiPt:), an
embedded tab or newline inside
the scheme (a browser's own URL parser strips these before reading the scheme,
per the WHATWG URL spec,
so a naive startsWith("javascript:") filter would miss them), and a leading
space or NUL.
Proposed fix (patch available): a new allowlist-based check (http, https,
mailto, tel), applied before
the existing quote/<script checks, with the same WHATWG-style normalization so
the tab/newline-split
variant is still caught. I have a patch with regression tests ready and will
open a PR referencing this
ticket.
> Reject javascript:/vbscript:/data: schemes in <s:a> href values
> ---------------------------------------------------------------
>
> Key: WW-5756
> URL: https://issues.apache.org/jira/browse/WW-5756
> Project: Struts 2
> Issue Type: Bug
> Components: Core
> Affects Versions: 6.11.0, 7.3.0, 7.4.0
> Reporter: Gouri Sankar A
> Priority: Major
>
> <s:a> builds its href attribute by neutralizing a literal quote (the href=
> attribute, via
> ensureAttributeSafelyNotEscaped) or blocking a literal "<script" substring
> (the value= attribute, via
> DefaultUrlHelper.buildUrl -- a check that appears to date back to
> S2-002/CVE-2008-6682, WW-2427, based
> on an exact symptom match with that historical ticket). Neither stops the
> value itself from naming an
> executable scheme: javascript:alert(1) needs no quote or <script substring to
> run once the link is
> activated.
> Reproduced on main (7.5.0-SNAPSHOT) and confirmed the same vulnerable code is
> present unchanged in
> 6.11.0, 7.3.0 and 7.4.0. Tested with embedded Tomcat 10.1.34, stock
> struts-default, one
> @StrutsParameter-bound action property q (the documented tag-attribute
> pattern):
> <s:a href="%\{q}"> q=javascript:alert(document.cookie) -> <a
> href="javascript:alert(...)">
> <s:a value="%\{q}"> q=javascript:alert(document.cookie) -> <a
> href="javascript:alert(...)">
> <s:a anchor="%\{q}"> q=javascript:alert(document.cookie) -> lands as a
> URL fragment, inert (safe)
> Also confirmed vulnerable before a fix: case variation (JaVaScRiPt:), an
> embedded tab or newline inside
> the scheme (a browser's own URL parser strips these before reading the
> scheme, per the WHATWG URL spec,
> so a naive startsWith("javascript:") filter would miss them), and a leading
> space or NUL.
> Proposed fix (patch available): a new allowlist-based check (http, https,
> mailto, tel), applied before
> the existing quote/<script checks, with the same WHATWG-style normalization
> so the tab/newline-split
> variant is still caught. I have a patch with regression tests ready and will
> open a PR referencing this
> ticket.
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