Malicious PDF — malware analysis report

Static analysis result for SHA-256 31e9a2f28b67f1c2…

MALICIOUS

PDF

78.9 KB Created: 2021-09-08 12:31:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 5eb327fd681c551397b3bea1d8b71ee0 SHA-1: 4bcdb5a041519488adf9a430f00c7388367cef1e SHA-256: 31e9a2f28b67f1c2b9bb6330c42ca92d0f687067500a24e16ee3f07f1ce47b72
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The file was detected by ClamAV as a phishing trojan and flagged by an ML classifier. It contains numerous external links, many pointing to compromised CMS upload directories, suggesting a phishing or malware distribution lure. The PDF structure itself is also noted as having duplicate object bodies, which can sometimes be used to obfuscate malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://knowleangling.co.uk/ckfinder/userfiles/files/rubimunafab.pdf In PDF document text
    • https://mosaicopeoplecorporation.com/ckfinder/userfiles/files/vakopubitezabuf.pdfIn PDF document text
    • http://motivationandmomentum.net/ci/userfiles/files/rufewatogoje.pdfIn PDF document text
    • https://abril.pe/wp-content/plugins/super-forms/uploads/php/files/caea7uj4r33umno7bej6559e2r/ropakod.pdfIn PDF document text
    • http://frederickfollows.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1613409eeb3d29---gobetavefunosu.pdfIn PDF document text
    • https://dongytueduc.com/wp-content/plugins/super-forms/uploads/php/files/5cf4c2mll0cq32pdibdr64v2vq/sotobum.pdfIn PDF document text
    • http://europeanprofservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/161313feb3e481---43280123928.pdfIn PDF document text
    • https://braus.uz/images/shared/file/37662073643.pdfIn PDF document text
    • https://tortugafilms.ca/adminfiles/file/60821681025.pdfIn PDF document text
    • http://bbmeti.it/userfiles/files/fapewaze.pdfIn PDF document text
    • http://www.sport-konyv.hu/userfiles/file/84907374938.pdfIn PDF document text
    • http://brukbet.com/user_images/file/76849562641.pdfIn PDF document text
    • http://pk.mo/userfiles/file/lipuvivusomewu.pdfIn PDF document text
    • https://qwert5.com/psum/admin/userfiles/file/56570482519.pdfIn PDF document text
    • https://www.adler-leitishofen.de/wp-content/plugins/formcraft/file-upload/server/content/files/1613739a9d1b69---63534149816.pdfIn PDF document text
    • https://aglogistics-bo.net/userfiles/file/napevudo.pdfIn PDF document text
    • http://www.clc-engineering.com/siteuploads/editorimg/file/xefovewixokekagapugariwo.pdfIn PDF document text
    • http://www.findvoters.com/userfiles/file/negaxabo.pdfIn PDF document text
    • http://sin-hua.org/userfiles/29241819457.pdfIn PDF document text
    • http://gdlianyu.com/uploadfiles/file/kurasitatabexufiref.pdfIn PDF document text
    • http://cnwt.mgo.cool/upfile/files/2021/09/07/68727490975.pdfIn PDF document text
    • https://dongytueduc.com/wp-content/plugins/super-forms/uploads/php/files/ibt1i9jdnum3lbar8nh7q2dhrj/werezunuzozatuveridid.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=church+choir+music+pdfPDF link annotation
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000cf8c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCF8C 18020 bytes
SHA-256: 6ff0ce088574591a74127197e5cf4edb7eec241013aa105b203db668f3fccfc6
font_01_sfnt_off0000fe7e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE7E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011695.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11695 10476 bytes
SHA-256: b6c0238c1508387bfd299daecf9f255e56f40ee4a13bfe6d123594cc704427ba