Malicious PDF — malware analysis report

Static analysis result for SHA-256 8bf79d64d182da8a…

MALICIOUS

PDF

93.5 KB Created: 2021-09-16 05:16:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: b2374225655f068c125ff4c8074ec385 SHA-1: 62ad467d081b5c5c2e1ab3ec89eb7e7f194654d6 SHA-256: 8bf79d64d182da8af8406ec36d3d43fbb2b0836df34e73b69f0eb3051edc5bc7
156 Risk Score

Malware Insights

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

The PDF file was identified as malicious by ML classifiers and ClamAV, specifically flagged as a phishing trojan. Heuristics indicate it functions as a link farm, with many URLs pointing to compromised WordPress sites and potentially disposable hosting. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather as a container for these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9935

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://abril.pe/wp-content/plugins/super-forms/uploads/php/files/aq1igcrcjojvmkhvbol5uqadvr/36133161816.pdf
    • https://birutelorasin.com/contents/files/sulelove.pdf
    • https://www.lowdoc-loans.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16132a0f5229b4---80915640707.pdf
    • http://icltindia.in/userfiles/file/56925838866.pdf
    • http://muaah.ca/userfiles/files/guvovip.pdf
    • https://santa.my/images/users/00000000/files/sosapigilisilanukifib.pdf
    • http://vejwun.cz/images/50299483305.pdf
    • http://pngroup.pl/ckfinder/userfiles/files/rarurugovalusetez.pdf
    • http://cbcom.eu/ressource/site-image/files/41956627129.pdf
    • http://855solution.com/htdocs/cljr/data/files/wabanonejoveriwosu.pdf
    • http://jadever.vn/Images_upload/files/timegesuxo.pdf
    • http://nmways.com/uploads/fckupload/file/20899983684.pdf
    • http://sts-logistika.ru/wp-content/plugins/super-forms/uploads/php/files/cb6d5ebf9f9d31d459aad8025f576829/gawimubarewotavufo.pdf
    • https://trucraftsmanship.com/wp-content/plugins/formcraft/file-upload/server/content/files/161366abc5268e---10809059322.pdf
    • https://best-of-geldanlagen.de/userfiles/file/91235510012.pdf
    • https://buddingheights.org/wp-content/plugins/formcraft/file-upload/server/content/files/1614123a958dbf---37238511509.pdf
    • https://armagedonspedycja.pl/files/file/sawiji.pdf
    • http://colorfulmedia.de/fotki/fotki/file/fuguzubamepot.pdf
    • https://metrosecuritynepal.com/assets/userfiles/files/turarite.pdf
    • http://sochi-vitrazhi.ru/ckfinder/userfiles/files/48941719040.pdf
    • http://copy2d.com/ftp/image/file/zuzimubejarinejigevosifi.pdf
    • http://seattleteriyaki3.com/uploads/files/fopuvorudunux.pdf
    • https://relaxbotanika.cz/ckfinder/userfiles/files/tiwizenozadefaza.pdf
    • http://goldmustang.ru/files/files/56408595727.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/BkSY9tpko7c/uplcv?utm_term=small+things+to+build+in+minecraft+survival
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0001013b.bin
52697ba4cb5d892c415d4801384c464ed7ac1156ef51a94301d453ecf28cd278
pdf-font-stream PDF embedded font (sfnt) at offset 0x1013B 20080 bytes
font_01_sfnt_off000135dd.bin
d28e5f94e71192245e3697c2d005b420c3332ed617e8db4a338c7beda562824b
pdf-font-stream PDF embedded font (sfnt) at offset 0x135DD 11304 bytes
font_02_sfnt_off00015004.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x15004 16792 bytes