Cloud safety firm Wiz has revealed that it uncovered in-the-wild exploitation of a safety flaw in a Linux utility referred to as Pandoc as a part of assaults designed to infiltrate Amazon Internet Companies (AWS) Occasion Metadata Service (IMDS).
The vulnerability in query is CVE-2025-51591 (CVSS rating: 6.5), which refers to a case of Server-Facet Request Forgery (SSRF) that permits attackers to compromise a goal system by injecting a specifically crafted HTML iframe aspect.
The EC2 IMDS is a vital element of the AWS cloud atmosphere, providing details about working situations, in addition to short-term, short-lived credentials if an id and entry administration (IAM) function is related to the occasion. The occasion metadata is accessible to any utility working on an EC2 occasion through a link-local deal with (169.254.169[.]254).
These credentials can then be used to securely work together with different AWS providers like S3, RDS, or DynamoDB, allowing purposes to authenticate with out the necessity for storing credentials on the machine, thereby decreasing the danger of unintentional publicity.
One of many widespread strategies that attackers can use to steal IAM credentials from IMDS is through SSRF flaws in internet purposes. This basically includes tricking the app working on an EC2 occasion to ship a request in search of IAM credentials from the IMDS service on its behalf.
“If the appliance can attain the IMDS endpoint and is vulnerable to SSRF, the attacker can harvest short-term credentials with no need any direct host entry (resembling RCE or path traversal),” Wiz researchers Hila Ramati and Gili Tikochinski mentioned.
An adversary trying to goal AWS infrastructure can subsequently seek for SSRF vulnerabilities in internet purposes working on EC2 situations and, when discovered, entry the occasion metadata and steal IAM credentials. This isn’t a theoretical risk.
Way back to early 2022, Google-owned Mandiant discovered {that a} risk actor it tracks as UNC2903 had attacked AWS environments by abusing credentials obtained utilizing IMDS since July 2021, exploiting an SSRF flaw (CVE-2021-21311, CVSS rating: 7.2) in Adminer, an open-source database administration instrument, to facilitate information theft.
The problem, at its core, stems from the truth that IMDS, or extra particularly IMDSv1, is a request and response protocol, making it a horny goal for unhealthy actors who goal exploitable internet purposes that additionally run IMDSv1.
In a report revealed final month, Resecurity warned that when SSRF is exploited in opposition to cloud infrastructure like AWS, it may well have “extreme and far-reaching” penalties, leading to cloud credential theft, community reconnaissance, and unauthorized entry to inner providers.
“Since SSRF originates from throughout the server, it may well attain endpoints protected by perimeter firewalls. This successfully turns the susceptible utility right into a proxy, permitting the attacker to: Bypass IP whitelists [and] attain in any other case unreachable inner property,” it mentioned.
The most recent findings from Wiz reveal that assaults focusing on the IMDS service are persevering with to happen, with adversaries leveraging SSRF vulnerabilities in little-known purposes like Pandoc to allow them.
“The vulnerability, tracked as CVE-2025-51591, stems from Pandoc rendering
“The attacker submitted crafted HTML paperwork containing
Wiz mentioned the assault was finally unsuccessful due to the enforcement of IMDSv2, which is session-oriented and mitigates the SSRF assault by first requiring a consumer to get a token and use that token in all requests to the IMDS through a particular header (X-aws-ec2-metadata-token).
The corporate informed The Hacker Information that it noticed in-the-wild exploitation makes an attempt “courting again to August and persevering with for a couple of weeks,” including it additionally discovered continued efforts on the a part of unknown risk actors to abuse one other SSRF flaw in ClickHouse to unsuccessfully breach a goal’s Google Cloud Platform.
To mitigate the danger posed by CVE-2025-51591 in cloud environments, it is suggested to make use of the “-f html+raw_html” choice or the “–sandbox” choice to stop Pandoc from together with the contents of iframe parts by means of the src attribute.
“[Pandoc maintainers] determined that rendering iframes is the meant habits and that the consumer is accountable to both sanitize the enter or use the sandbox flags when dealing with consumer inputs,” Wiz mentioned.
“Though Amazon recommends implementing the IMDSv2 with GuardDuty enhancements, EC2 situations created by Amazon clients that as an alternative use IMDSv1 could also be in danger when mixed with additionally working unpatched susceptible third celebration software program,” Mandiant researchers warned on the time.
Organizations are really useful to implement IMDSv2 throughout all EC2 situations and be certain that situations are assigned roles that comply with the precept of least privilege (PoLP) to include the blast radius within the occasion of an IMDS compromise.
