Malicious PDF — malware analysis report

Static analysis result for SHA-256 2090114d5cc2c1e1…

MALICIOUS

PDF

74.2 KB Created: 2021-03-14 14:38:57 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-07
MD5: ba66aee40ad0834b1eb90256dc8a59d4 SHA-1: 669dc0ea34c8224cd19efb3a5839825857b32478 SHA-256: 2090114d5cc2c1e154ba1add6a82433ffaef0e4060214871fa3cbfc02d7c3688
184 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The sample is a PDF file identified as malicious by multiple heuristics, including a critical alert for linking to known malicious redirector infrastructure. The ML classifier also strongly flagged it. The embedded URL `https://yafferge.ru/wix?keyword=math+32a+ucla+midterm` is a primary indicator of malicious intent, likely serving as a lure or redirector. The document body, though heavily obfuscated, contains metadata suggesting it was generated by wkhtmltopdf, a tool sometimes used to create malicious PDFs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

Heuristics 5

  • 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 links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • 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.
  • 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://yafferge.ru/wix?keyword=math+32a+ucla+midterm In PDF document text
    • http://zonamumajotodot.iblogger.org/dd_players_handbook_used.pdfIn PDF document text
    • http://ejinaya.com/nanumiliikudb.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4481695/normal_5fe599fec56f0.pdfIn PDF document text
    • http://podemufibe.iblogger.org/9570659292.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4389801/normal_5fe42e9fea4c5.pdfIn PDF document text
    • http://koteyarn.moscow/game_of_thrones_beyond_the_wall_episode_reviewzywwj.pdfIn PDF document text
    • http://siditomema.22web.org/78828108824.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4368736/normal_601964c9ee199.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4501980/normal_5ff21fa8459f3.pdfIn PDF document text
    • http://persequen.com/alliance_guns_of_gloryj4zer.pdfIn PDF document text
    • http://copalofa.site/busch_gardens_williamsburg_map_2020zeyeb.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4416305/normal_60126d9708c43.pdfIn PDF document text
    • http://copyright-security-ig.com/the_castle_of_otranto_sparknotes_chapter_1bubo5.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/b33e0173-84a2-4404-8d74-c6bcc1544b83/what_to_do_with_a_phd_in_molecular_biology.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/35778e07-9195-4c58-b4b2-2aa13ee4e0dd/how_to_make_a_simple_homemade_chicken_coop.pdfIn PDF document text
    • http://xesesopid.rf.gd/faux_leather_fabric_sheets.pdfIn PDF document text
    • http://wewepov.rf.gd/bash_script_argument_string_spaces.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/58a7873c-d9a3-4d35-a59a-32ff06def8c3/little_shop_of_horrors_songs_feed_me.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/d1ffdcb8-01db-4bab-af1a-45451925af66/tijipil.pdfIn PDF document text
    • http://dinelak.rf.gd/nalefazefopuz.pdfIn PDF document text
    • http://fuxedozet.epizy.com/98885171196.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/0fe5009c-4a97-40e0-bf06-fc5a11e9041b/21779087079.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/be64700b-74a4-4375-9a46-0c44b79c38d6/43781118125.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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e31a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE31A 5300 bytes
SHA-256: aae41f726e3d94e8b861765559a63474ddbec15a9689c98e44ab3fd408bd5cf0
font_01_sfnt_off0000f501.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF501 11332 bytes
SHA-256: 29a67492c6d870bac2fddce6379dfd8b2b025f076ad0cdc45dc1b3f9499cd915