Malicious PDF — malware analysis report

Static analysis result for SHA-256 31d8e024a5a064d1…

MALICIOUS

PDF

86.4 KB Created: 2021-09-17 14:10:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: fea1f65fef7af697a2fa8a63b08064df SHA-1: cdbd00c1cc932ab68a2b7ff3bed934b6a1432ff7 SHA-256: 31d8e024a5a064d18fda323d5f1ea5f92078f4d91505d300318a77cf01af9162
176 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URIs pointing to various domains, many of which are associated with compromised CMS uploads or disposable hosting, indicating a link farm designed to redirect users. The ClamAV detection and ML classifier strongly suggest malicious intent, likely for phishing or malware distribution. Although no scripts were explicitly extracted, the PDF structure and URI patterns are consistent with techniques used to deliver second-stage payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Clickable URI points to raw IP address medium PDF_URI_IP_LITERAL
    PDF contains a clickable HTTP(S) action whose host is a literal IPv4 address. Legitimate documents normally link to named domains; raw-IP destinations are common in disposable phishing and malware-delivery infrastructure.
  • 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://krisoc.ru/uplcv?utm_term=introduction+to+logic+and+critical+thinking+6th+edition+pdf PDF link annotation
    • http://youngthisyear.com/ckfinder/userfiles/files/kiloxizililigogefove.pdfIn PDF document text
    • http://vipacademy.org/userfiles/file/timibaxutasu.pdfIn PDF document text
    • https://nsstore.mx/ckeditor/ckfinder/archivossubidos/files/87933032147.pdfIn PDF document text
    • http://www.birapart.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612fd8d919658---62918858827.pdfIn PDF document text
    • http://robotsuk.com/luckingbros.co.uk/userfiles/files/zivilowamimokajowovalopad.pdfIn PDF document text
    • http://321eastern-thailand.com/userfiles/files/70691615014.pdfIn PDF document text
    • http://aburobocon2019.mnb.mn/uploads/files/danamoxolojer.pdfIn PDF document text
    • http://europeanprofservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/16134db1ca0d98---4053121410.pdfIn PDF document text
    • https://kluchar.net/klucharnet/images/file/38745699662.pdfIn PDF document text
    • https://tapuionoticias.com/ckfinder/files/20986544729.pdfIn PDF document text
    • http://globalnetworks.de/www.galabau-poscher.de/main/preview/ckfinder/userfiles/files/deraloxap.pdfIn PDF document text
    • http://liubeauty.com/luutru/files/xinowemiwu.pdfIn PDF document text
    • http://140.121.125.49/ckfinder/userfiles/files/20210911_075140.pdfPDF link annotation
    • http://uran-berlin.com/userfiles/file/muved.pdfIn PDF document text
    • http://immobilieninvestors.com/userfiles/file/gobarenegofilinuseg.pdfIn PDF document text
    • https://brihat-group.com/assets/userfiles/files/tekimin.pdfIn PDF document text
    • https://www.auditek.fr/wp-content/plugins/formcraft/file-upload/server/content/files/16133fc9c735eb---vamibesomegefoziki.pdfIn PDF document text
    • 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_off0000e8f3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE8F3 19028 bytes
SHA-256: 23710a7c59d92baf88c4ce37f34e101780e444c6cf828a9f9c2887d0fd0ce197
font_01_sfnt_off00011a7d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11A7D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00013294.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13294 11044 bytes
SHA-256: e45146f8c6816b8baaa69b3c98b2fd9ef6d8c1d45b81ad45e812d8531b45a44c