Malicious PDF — malware analysis report

Static analysis result for SHA-256 c53d2c60b5de444a…

MALICIOUS

PDF

70.8 KB Created: 2021-09-11 05:15:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 5313e7ddc98ad0bbf716e19a3c620aaf SHA-1: 3781939ea13c160d9444439e5d4008bfbadb37ee SHA-256: c53d2c60b5de444a9f9162cdc30e3e0b21b433e2010b8e0449d57d92931b3266
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file flagged by ML classifiers and ClamAV as malicious. It contains numerous embedded URLs, many of which point to compromised CMS uploads or disposable hosting, indicating a link farm designed for phishing or malware distribution. While no scripts were directly extracted, the PDF structure and embedded URLs suggest an attempt to lure users to external sites, likely as part of a phishing campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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 https://cualuoihoanmy.com/uploads/userfiles/file/boxepenamalofeju.pdf In PDF document text
    • https://nepalonetours.com/userfiles/files/5113839980.pdfIn PDF document text
    • http://niezapominajkowo.eu/userfiles/file/vezawifewej.pdfIn PDF document text
    • https://www.projectorrentals.com/wp-content/plugins/formcraft/file-upload/server/content/files/161359dad403c2---dovazugizaj.pdfIn PDF document text
    • http://www.peritaonline.es/ckfinder/userfiles/files/99219947541.pdfIn PDF document text
    • http://bjoybrands.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613748da5b3c5---4142620243.pdfIn PDF document text
    • http://chenruichem.com/upload/files/fosokerivowovorumo.pdfIn PDF document text
    • https://kisikana.hr/UserFiles/files/mavamuno.pdfIn PDF document text
    • https://booburger.myagenda.cz/pictures/editor/files/15774453138.pdfIn PDF document text
    • http://restavratorstvo.com/ckfinder/userfiles/files/satotelisigixez.pdfIn PDF document text
    • http://geologocarmignani.com/userfiles/files/zopofonabemef.pdfIn PDF document text
    • http://rasmesafar.net/basefile/basefiles/28926995143.pdfIn PDF document text
    • http://isemya.by/modules/ariol/static/ariol/ckfinder/files/vanadonixetimomexe.pdfIn PDF document text
    • https://die-elke.de/cms/elke_page_files/file/36285269130.pdfIn PDF document text
    • http://vibrobeton.by/pics/files/nuxuso.pdfIn PDF document text
    • http://www.heksan.com.pl/file/6924427642.pdfIn PDF document text
    • https://transcendenceit.com/wp-content/plugins/super-forms/uploads/php/files/6e5f54101bfc4c437a14fc9cdbb2488d/91227698619.pdfIn PDF document text
    • https://www.sibirprokat.ru/ckfinder/userfiles/files/12264107045.pdfIn PDF document text
    • http://prplus4u.com/ckupload/files/44456825177.pdfIn PDF document text
    • http://energy-labels.com/userfiles/file/vuxamebopanomefugifin.pdfIn PDF document text
    • http://clean-ecology.com/Upload/files/mekuxatinebodamamanugipez.pdfIn PDF document text
    • https://perfecthospitals.org/ckfinder/userfiles/files/52148153603.pdfIn PDF document text
    • https://csp-pub.com/stockages/files/zizosuroza.pdfIn PDF document text
    • http://effektfilm.de/files/file/41661695914.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1KS0DP0cxss/uplcv?utm_term=pokemon+fire+red+filePDF 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_off0000b5c3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB5C3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cdda.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCDDA 10180 bytes
SHA-256: 5202c86cc2cc2eda8aa26ba1cb8367ad0f4fe4efe6c1171fa5a69f8c97729410
font_02_sfnt_off0000e488.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE488 16020 bytes
SHA-256: ab79f4f7140b24cd369c81333a69e7411245d67350adc82c595f975990c03dfa