Malicious PDF — malware analysis report

Static analysis result for SHA-256 55f5e5fb35c6d22b…

MALICIOUS

PDF

48.3 KB Created: 2020-07-28 15:41:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: de058672a7b1da6e2fbdb104161e1365 SHA-1: 6c37d04a726d9d4a9bb5bba09431d7a7aa00fa53 SHA-256: 55f5e5fb35c6d22b36d8e005ce5c1b7757442596aa1b663dcbf66c9312a76332
152 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1059.001 PowerShell

The PDF contains a critical heuristic firing for a malicious redirector link, which is further supported by the presence of numerous external PDF links, many hosted on cdn.shopify.com. The document body, though heavily obfuscated, contains text related to 'free printable math worksheets', suggesting a lure. The primary malicious IOC is the redirector URL, which likely leads to further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 4

  • 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 contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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://ttraff.cc/pify?keyword=first+grade+free+printable+math+worksheets
    • http://files.travelsinacab.com/uploads/1/3/1/3/131384113/lazanizakowomuse.pdf
    • http://files.klamathforestestates4rma.org/uploads/1/3/1/1/131164425/zegamabunaj_rafixuwumo.pdf
    • http://files.nzrespiratoryguidelines.co.nz/uploads/1/3/0/8/130814200/eb58fd7e3.pdf
    • https://cdn.shopify.com/s/files/1/0431/6332/0471/files/48333860620.pdf
    • https://cdn.shopify.com/s/files/1/0434/0776/9750/files/24691326474.pdf
    • https://cdn.shopify.com/s/files/1/0433/0032/3478/files/87374790660.pdf
    • https://cdn.shopify.com/s/files/1/0432/2764/4072/files/wulibupuxozunetazolubinor.pdf
    • https://cdn.shopify.com/s/files/1/0428/9835/8432/files/10809735118.pdf
    • https://cdn.shopify.com/s/files/1/0428/2528/5798/files/69250824874.pdf
    • https://cdn.shopify.com/s/files/1/0431/3543/4901/files/nusesudalaxamoxire.pdf
    • https://cdn.shopify.com/s/files/1/0431/7301/9808/files/bevolorolimisakozodafe.pdf
    • https://cdn.shopify.com/s/files/1/0433/0687/7080/files/mipubafuminidumef.pdf
    • https://cdn.shopify.com/s/files/1/0434/0265/7957/files/javajetazonuxos.pdf
    • https://cdn.shopify.com/s/files/1/0432/4635/4592/files/59168632331.pdf
    • https://cdn.shopify.com/s/files/1/0428/5287/6455/files/lataxufu.pdf
    • https://cdn.shopify.com/s/files/1/0428/2833/3219/files/zemasupidepes.pdf
    • https://cdn.shopify.com/s/files/1/0434/2834/8056/files/jebubodovufo.pdf
    • 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/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00007e39.bin
7743dd91899c3e2d72e3f65d47e34cd19a8fa8a7b4f24e417e195ed830efd11f
pdf-font-stream PDF embedded font (sfnt) at offset 0x7E39 5492 bytes
font_01_sfnt_off000090be.bin
abb079bc7a69cbd3422e59f1eacf0c115aa5f780adbfbea3112d0636e1a85d45
pdf-font-stream PDF embedded font (sfnt) at offset 0x90BE 10300 bytes