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HomeCyber SecurityApache Commons Textual content RCE flaw — Maintain calm and patch away

Apache Commons Textual content RCE flaw — Maintain calm and patch away


A distant code execution flaw within the open-source Apache Commons Textual content library has some individuals fearful that it may flip into the subsequent Log4Shell. Nevertheless, most cybersecurity researchers say it’s nowhere close to as regarding.

Apache Commons Textual content is a well-liked open-source Java library with an “interpolation system” that enables builders to switch, decode, generate, and escape strings based mostly on inputted string lookups.

For instance, passing the string lookup ${base64Decoder:SGVsbG9Xb3JsZCE=} to the interpolation system would trigger the library to transform it to its base64 decoded worth of ‘HelloWorld!’.

The brand new CVE-2022-42889 vulnerability in Apache Commons Textual content, dubbed “Text4Shell,” is attributable to unsafe script analysis by the interpolation system that would set off code execution when processing malicious enter within the library’s default configuration.

“Beginning with model 1.5 and persevering with via 1.9, the set of default Lookup cases included interpolators that would lead to arbitrary code execution or contact with distant servers,” particulars a developer within the Apache mailing checklist.

“Functions utilizing the interpolation defaults within the affected variations could also be susceptible to RCE or unintentional contact with distant servers if untrusted configuration values are used.”

“Customers are really useful to improve to Apache Commons Textual content 1.10.0, which disables the problematic interpolators by default.”

The difficulty was found by GitHub’s risk analyst Alvaro Munoz and reported to Apache on March 9, 2022.

Nevertheless, it took the open-source library builders 7 months, till October 12, 2022, to launch a repair in model 1.10.0, which disables interpolation.

Must you fear?

As a result of widespread deployment of the susceptible library, and for the reason that flaw impacts variations that date way back to 2018, some initially fearful that it may trigger widespread injury, as we noticed with the Log4Shell vulnerability.

Nevertheless, a report from Rapid7 rapidly put a brake to those issues, explaining that not all variations between 1.5 and 1.9 appear susceptible and that its exploitation potential was linked to the JDK model used.

Even with an up to date proof of idea (PoC) exploit utilizing the JEXL engine as an exploit path bypasses the JDK limitation, researchers are nonetheless not very involved.

New PoC working on all vulnerable versions
New PoC engaged on all susceptible variations (@pwntester)

Moreover, Apache’s safety crew has mentioned that the scope of the flaw is just not a critical as Log4Shell, explaining that the string interpolation is a documented function. Due to this fact, it’s much less seemingly that purposes utilizing the library would inadvertently go unsafe enter with out validation.

Whereas the important severity flaw remained unpatched for seven months and uncovered to exploitation makes an attempt, there have been no stories of abuse within the wild even after exploits have been launched.

Whereas we’ll seemingly see some risk actors exploiting CVE-2022-42889 sooner or later, it’ll in all probability be restricted in scope.

For now, all builders using the Apache Commons Textual content library are suggested to improve to model 1.10 or later as quickly as potential to repair the flaw.

Safety researcher Sean Wright warns that some Java tasks preserve all library class recordsdata in a single jar and can should be scanned independently.

Sean Wright tweet

To help find susceptible variations of the Apache Commons Textual content library, Silent Sign has launched a Burp plugin that may scan apps for parts unpatched towards CVE-2022-42889.



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