Cloud safety firm Wiz has revealed that it uncovered in-the-wild exploitation of a safety flaw in a Linux utility known as Pandoc as a part of assaults designed to infiltrate Amazon Net 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-Aspect Request Forgery (SSRF) that permits attackers to compromise a goal system by injecting a specifically crafted HTML iframe aspect.
The EC2 IMDS is an important element of the AWS cloud setting, providing details about working cases, in addition to momentary, short-lived credentials if an id and entry administration (IAM) function is related to the occasion. The occasion metadata is accessible to any software working on an EC2 occasion through a link-local handle (169.254.169[.]254).
These credentials can then be used to securely work together with different AWS providers like S3, RDS, or DynamoDB, allowing functions to authenticate with out the necessity for storing credentials on the machine, thereby lowering the chance of unintended publicity.
One of many frequent strategies that attackers can use to steal IAM credentials from IMDS is through SSRF flaws in net functions. This primarily entails tricking the app working on an EC2 occasion to ship a request looking for IAM credentials from the IMDS service on its behalf.
“If the appliance can attain the IMDS endpoint and is inclined to SSRF, the attacker can harvest momentary credentials while not having any direct host entry (corresponding to RCE or path traversal),” Wiz researchers Hila Ramati and Gili Tikochinski mentioned.
An adversary seeking to goal AWS infrastructure can due to this fact seek for SSRF vulnerabilities in net functions working on EC2 cases 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 software, to facilitate information theft.
The difficulty, at its core, stems from the truth that IMDS, or extra particularly IMDSv1, is a request and response protocol, making it a pretty goal for dangerous actors who goal exploitable net functions that additionally run IMDSv1.
In a report printed final month, Resecurity warned that when SSRF is exploited in opposition to cloud infrastructure like AWS, it could possibly have “extreme and far-reaching” penalties, leading to cloud credential theft, community reconnaissance, and unauthorized entry to inside providers.
“Since SSRF originates from throughout the server, it could possibly attain endpoints protected by perimeter firewalls. This successfully turns the weak software right into a proxy, permitting the attacker to: Bypass IP whitelists [and] attain in any other case unreachable inside belongings,” it mentioned.
The most recent findings from Wiz show that assaults concentrating on the IMDS service are persevering with to happen, with adversaries leveraging SSRF vulnerabilities in little-known functions 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 advised The Hacker Information that it noticed in-the-wild exploitation makes an attempt “courting again to August and persevering with for just a few 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 chance 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 forestall Pandoc from together with the contents of iframe components by 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 cases created by Amazon prospects that as an alternative use IMDSv1 could also be in danger when mixed with additionally working unpatched weak third celebration software program,” Mandiant researchers warned on the time.
Organizations are really helpful to implement IMDSv2 throughout all EC2 cases and be certain that cases are assigned roles that observe the precept of least privilege (PoLP) to include the blast radius within the occasion of an IMDS compromise.
