Malicious PDF — malware analysis report

Static analysis result for SHA-256 36a428bfd1dbabbe…

MALICIOUS

PDF

85.8 KB Created: 2021-06-30 10:58:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: ee3712a1178728430640dbc2eb355dea SHA-1: 70ac170fbd44ef10b9e51540b4ea874adff1d58d SHA-256: 36a428bfd1dbabbe01905df0bd229d30c5bcedf5791de6a3624a320bfd1eb3a9
156 Risk Score

Malware Insights

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

The sample is identified as malicious by ML classifiers and ClamAV, specifically as a phishing trojan. It functions as a link farm, with numerous URLs pointing to compromised CMS upload directories, likely intended to host and distribute further malicious content. The PDF document body is heavily obfuscated and contains no readable text, suggesting its primary purpose is to deliver these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9952

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 http://kennyre.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bbc9aa2c3f9---romuwijerad.pdf
    • http://brezov-gaj.si/uporabnik/file/wigekuwu.pdf
    • http://konditsionery-reutov.ru/upload_picture/file/74785725627.pdf
    • https://medtek.vn/storage/file/bakiwebogonisek.pdf
    • https://nowackleverkusen.de/wp-content/plugins/formcraft/file-upload/server/content/files/160a4cac97cbcc---11627065572.pdf
    • http://breakevenpoint.pl/uploads/editor/file/20783611738.pdf
    • http://www.k-24.com/wp-content/plugins/formcraft/file-upload/server/content/files/160847f897f41f---sivizeba.pdf
    • http://dianacb.cz/userfiles/file/94430685238.pdf
    • https://ivfnna.gr/wp-content/plugins/super-forms/uploads/php/files/cf9fde56a616a153c918d78f299c161a/94856084800.pdf
    • http://cke.hk/userfiles/6767579161.pdf
    • https://miamiuniquelimo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607c63cd5b772---7803995158.pdf
    • https://www.basur-tedavisi.com/wp-content/plugins/formcraft/file-upload/server/content/files/16074c2264c119---41588790950.pdf
    • https://iveducentar.com/uploads/assets/file/6570627391.pdf
    • http://www.pirac.org/wp-content/plugins/super-forms/uploads/php/files/82d37e8eacce040529095120c35763d6/tuxojamoxanopi.pdf
    • http://www.farparts.cl/wp-content/plugins/formcraft/file-upload/server/content/files/160b56dc861c47---jijajeta.pdf
    • https://exporoaster.com/app/webroot/files/images/pages/files/65755436646.pdf
    • https://sandalyecenneti.com/wp-content/plugins/super-forms/uploads/php/files/nui3nurhbb39llf1228ulf0u1v/14938095547.pdf
    • https://e-lightingcontrols.com/wp-content/plugins/super-forms/uploads/php/files/076bd634e14a1482745a3a07777df058/46867458314.pdf
    • http://popnmusic.fr/userfiles/file/wojinaken.pdf
    • https://ahi.com.ua/wp-content/plugins/super-forms/uploads/php/files/67dedae09a0365d90aa478cd0de6fb4e/kifupafemadezin.pdf
    • https://www.charroninc.com/wp-content/plugins/super-forms/uploads/php/files/e39eff53c9b3f26ebbe4369a56cab4dd/dafevategasaxadebatepu.pdf
    • http://www.christinemartin.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160b053cecc2f7---tiwaw.pdf
    • http://xn--80aafkqcanfpgnhbng3b5i9a.xn--p1ai/pict/file/46812736759.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/A3Ryygt5BCM/uplcv?utm_term=comparing+text+structures
    • 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_off0000eaa7.bin
a74505caf42081842aeaf45f1a96084784b8abb6c947047b98a6c0d72b66525f
pdf-font-stream PDF embedded font (sfnt) at offset 0xEAA7 17132 bytes
font_01_sfnt_off00011758.bin
07d517930941ac0e8090e1ebb531ee5708f9d9c4ccf4cc81393d53059fbf4694
pdf-font-stream PDF embedded font (sfnt) at offset 0x11758 10904 bytes
font_02_sfnt_off000130a1.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x130A1 16792 bytes